Номер 853, страница 218 - гдз по геометрии 10-11 класс учебник Атанасян, Бутузов

Геометрия, 10-11 класс Учебник, авторы: Атанасян Левон Сергеевич, Бутузов Валентин Фёдорович, Кадомцев Сергей Борисович, Позняк Эдуард Генрихович, Киселёва Людмила Сергеевна, издательство Просвещение, Москва, 2019, коричневого цвета

Авторы: Атанасян Л. С., Бутузов В. Ф., Кадомцев С. Б., Позняк Э. Г., Киселёва Л. С.

Тип: Учебник

Издательство: Просвещение

Год издания: 2019 - 2026

Уровень обучения: базовый и углублённый

Цвет обложки: коричневый с ромбами

ISBN: 978-5-09-103606-0 (2023)

Допущено Министерством просвещения Российской Федерации

Математика: алгебра и начала математического анализа, геометрия

Глава 8. Некоторые сведения из планиметрии. Параграф 3. Теоремы Менелая и Чевы - номер 853, страница 218.

App\Models\Task {#1030 // resources/views/models/task/default.blade.php
  #connection: "mysql"
  #table: "tasks"
  #primaryKey: "id"
  #keyType: "int"
  +incrementing: true
  #with: []
  #withCount: []
  +preventsLazyLoading: false
  #perPage: 15
  +exists: true
  +wasRecentlyCreated: false
  #escapeWhenCastingToString: false
  #attributes: array:24 [
    "id" => 745268
    "created_at" => "2026-04-10 13:58:26"
    "updated_at" => null
    "field_page_start" => "218"
    "field_page_end" => null
    "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/00-853"
    "field_display_title" => "853"
    "field_outside_task" => null
    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1037
      #items: array:1 [
        0 => App\Models\Term {#1036
          #connection: "mysql"
          #table: "terms"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: false
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:6 [
            "id" => 26
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "name" => "номер"
            "field_cases" => array:6 [
              "field_accusative_case" => "номер"
              "field_creative_case" => "номером"
              "field_dative_case" => "номеру"
              "field_genitive_case" => "номера"
              "field_nominative_case" => "номер"
              "field_prepositional_case" => "номере"
            ]
            "field_short_name" => ""
          ]
          #original: array:6 [
            "id" => 26
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "name" => "номер"
            "field_cases" => array:6 [
              "field_accusative_case" => "номер"
              "field_creative_case" => "номером"
              "field_dative_case" => "номеру"
              "field_genitive_case" => "номера"
              "field_nominative_case" => "номер"
              "field_prepositional_case" => "номере"
            ]
            "field_short_name" => ""
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "field_metatags_title" => null
    "field_metatags_description" => null
    "field_h1" => null
    "field_description_top" => null
    "field_description_bottom" => null
    "field_match" => null
    "breadcrumbs" => []
    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1035
      #items: []
      #escapeWhenCastingToString: false
    }
    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1046
      #items: array:1 [
        0 => App\Models\Branch {#1045
          #connection: "mysql"
          #table: "branches"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:24 [
            "id" => 744411
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Некоторые сведения из планиметрии"
            "field_branch_order" => "8"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1050
              #items: array:1 [
                0 => App\Models\Term {#1047
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:7 [
                    "id" => 29
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Глава"
                    "field_cases" => array:6 [ …6]
                    "field_page_check_not_needed" => null
                    "field_short_name" => null
                  ]
                  #original: array:7 [
                    "id" => 29
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Глава"
                    "field_cases" => array:6 [ …6]
                    "field_page_check_not_needed" => null
                    "field_short_name" => null
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "194"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1086
              #items: array:1 [
                0 => App\Models\Book {#1049
                  #connection: "mysql"
                  #table: "books"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:50 [
                    "id" => 36
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_tree_default_status" => "tasks"
                    "field_pages_status" => null
                    "field_subject" => Illuminate\Database\Eloquent\Collection {#1051
                      #items: array:1 [
                        0 => App\Models\Term {#1048
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:10 [
                            "id" => 6477
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Геометрия"
                            "field_abbreviated_name" => null
                            "field_cases" => array:6 [ …6]
                            "field_foreign_lang_name" => null
                            "field_short_name" => null
                            "field_subject_type" => "technical_subject"
                            "field_translit" => "geometrija"
                          ]
                          #original: array:10 [
                            "id" => 6477
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Геометрия"
                            "field_abbreviated_name" => null
                            "field_cases" => array:6 [ …6]
                            "field_foreign_lang_name" => null
                            "field_short_name" => null
                            "field_subject_type" => "technical_subject"
                            "field_translit" => "geometrija"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1052
                      #items: array:2 [
                        0 => App\Models\Term {#1053
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 5459
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "10"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "desjatyj"
                          ]
                          #original: array:6 [
                            "id" => 5459
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "10"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "desjatyj"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                        1 => App\Models\Term {#1054
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 5460
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "11"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "odinadcatyj"
                          ]
                          #original: array:6 [
                            "id" => 5460
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "11"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "odinadcatyj"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1055
                      #items: array:1 [
                        0 => App\Models\Term {#1056
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 5153
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Просвещение"
                            "field_cases" => null
                            "field_translit" => "prosveschenie"
                          ]
                          #original: array:6 [
                            "id" => 5153
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Просвещение"
                            "field_cases" => null
                            "field_translit" => "prosveschenie"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1057
                      #items: array:5 [
                        0 => App\Models\Term {#1058
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [
                            "id" => 3753
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Атанасян"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Левон"
                            "field_patronymic" => "Сергеевич"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 3753
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Атанасян"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Левон"
                            "field_patronymic" => "Сергеевич"
                            "field_surname_rp" => null
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                        1 => App\Models\Term {#1059
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [
                            "id" => 3949
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Бутузов"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Валентин"
                            "field_patronymic" => "Фёдорович"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 3949
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Бутузов"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Валентин"
                            "field_patronymic" => "Фёдорович"
                            "field_surname_rp" => null
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                        2 => App\Models\Term {#1060
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [
                            "id" => 4518
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Кадомцев"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Сергей"
                            "field_patronymic" => "Борисович"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 4518
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Кадомцев"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Сергей"
                            "field_patronymic" => "Борисович"
                            "field_surname_rp" => null
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                        3 => App\Models\Term {#1061
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [
                            "id" => 5494
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Позняк"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Эдуард"
                            "field_patronymic" => "Генрихович"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 5494
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Позняк"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Эдуард"
                            "field_patronymic" => "Генрихович"
                            "field_surname_rp" => null
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                        4 => App\Models\Term {#1062
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [
                            "id" => 6905
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Киселёва"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Людмила"
                            "field_patronymic" => "Сергеевна"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 6905
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Киселёва"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Людмила"
                            "field_patronymic" => "Сергеевна"
                            "field_surname_rp" => null
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1063
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1064
                      #items: array:1 [
                        0 => App\Models\Term {#1065
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:10 [
                            "id" => 6671
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Учебник"
                            "field_book_type_foreign" => null
                            "field_cases" => array:6 [ …6]
                            "field_plural_form" => null
                            "field_short_name" => null
                            "field_short_name_foreign" => null
                            "field_translit" => "uchebnik"
                          ]
                          #original: array:10 [
                            "id" => 6671
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Учебник"
                            "field_book_type_foreign" => null
                            "field_cases" => array:6 [ …6]
                            "field_plural_form" => null
                            "field_short_name" => null
                            "field_short_name_foreign" => null
                            "field_translit" => "uchebnik"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1066
                      #items: array:1 [
                        0 => App\Models\Term {#1067
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 9
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Россия"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "rossiya"
                          ]
                          #original: array:6 [
                            "id" => 9
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Россия"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "rossiya"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1068
                      #items: array:1 [
                        0 => App\Models\Term {#1069
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 15
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Москва"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "moskva"
                          ]
                          #original: array:6 [
                            "id" => 15
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Москва"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "moskva"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1070
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1071
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1072
                      #items: array:1 [
                        0 => App\Models\Term {#1073
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 41
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "базовый и углублённый"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "bazovyy i uglublennyy"
                          ]
                          #original: array:6 [
                            "id" => 41
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "базовый и углублённый"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "bazovyy i uglublennyy"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1074
                      #items: array:1 [
                        0 => App\Models\Term {#1075
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:10 [
                            "id" => 6706
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "ФГОС (старый)"
                            "field_cases" => array:6 [ …6]
                            "field_color" => null
                            "field_end_year" => "2022"
                            "field_start_year" => "2019"
                            "field_translit" => "fgos-old"
                            "field_type" => null
                          ]
                          #original: array:10 [
                            "id" => 6706
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "ФГОС (старый)"
                            "field_cases" => array:6 [ …6]
                            "field_color" => null
                            "field_end_year" => "2022"
                            "field_start_year" => "2019"
                            "field_translit" => "fgos-old"
                            "field_type" => null
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_publication_number" => "11"
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1076
                      #items: array:1 [
                        0 => App\Models\Term {#1077
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 33
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "стереотипное"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "stereotipnoe"
                          ]
                          #original: array:6 [
                            "id" => 33
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "стереотипное"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "stereotipnoe"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1078
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => "с ромбами"
                    "field_publication_year" => "2019"
                    "field_publication_year_until" => null
                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебник для общеобразовательных организаций"
                    "field_allowed" => "Допущено Министерством просвещения Российской Федерации"
                    "field_reserve_field" => "Математика: алгебра и начала математического анализа, геометрия"
                    "field_link_to_source" => null
                    "field_tasks_count" => "1147"
                    "field_priority" => "12"
                    "field_default_folder" => "/geometrija_10/atanasjan-u23/"
                    "field_isbn" => "978-5-09-103606-0 (2023)"
                    "field_cover" => array:1 [
                      0 => "/media/geometrija_10/atanasjan-u23/covers/cover1.webp?ts=1739363242"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/geometrija_10/atanasjan-u23/covers/cover1.webp?ts=1739363242"
                        "alt" => ""
                        "width" => "1200"
                        "height" => "1661"
                      ]
                    ]
                    "field_popular_book" => null
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1079
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1080
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1081
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_url" => "/10-klass/geometrija/atanasjan-uchebnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1082
                      #items: array:1 [
                        0 => App\Models\Term {#1083
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 51
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "коричневый"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "korichnevyy"
                          ]
                          #original: array:6 [
                            "id" => 51
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "коричневый"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "korichnevyy"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "breadcrumbs" => array:3 [
                      "class" => 381
                      "subject" => 543
                      "class_subject" => 392
                    ]
                  ]
                  #original: array:50 [
                    "id" => 36
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_tree_default_status" => "tasks"
                    "field_pages_status" => null
                    "field_subject" => Illuminate\Database\Eloquent\Collection {#1051}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1052}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1055}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1057}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1063}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1064}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1066}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1068}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1070}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1071}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1072}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1074}
                    "field_publication_number" => "11"
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1076}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1078}
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => "с ромбами"
                    "field_publication_year" => "2019"
                    "field_publication_year_until" => null
                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебник для общеобразовательных организаций"
                    "field_allowed" => "Допущено Министерством просвещения Российской Федерации"
                    "field_reserve_field" => "Математика: алгебра и начала математического анализа, геометрия"
                    "field_link_to_source" => null
                    "field_tasks_count" => "1147"
                    "field_priority" => "12"
                    "field_default_folder" => "/geometrija_10/atanasjan-u23/"
                    "field_isbn" => "978-5-09-103606-0 (2023)"
                    "field_cover" => array:1 [
                      0 => "/media/geometrija_10/atanasjan-u23/covers/cover1.webp?ts=1739363242"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/geometrija_10/atanasjan-u23/covers/cover1.webp?ts=1739363242"
                        "alt" => ""
                        "width" => "1200"
                        "height" => "1661"
                      ]
                    ]
                    "field_popular_book" => null
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1079}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1080}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1081}
                    "field_url" => "/10-klass/geometrija/atanasjan-uchebnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1082}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "breadcrumbs" => array:3 [
                      "class" => 381
                      "subject" => 543
                      "class_subject" => 392
                    ]
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1084
              #items: []
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 744411
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Некоторые сведения из планиметрии"
            "field_branch_order" => "8"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1050}
            "field_page_start" => "194"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1086}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1084}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1121
      #items: array:2 [
        0 => App\Models\Branch {#1129
          #connection: "mysql"
          #table: "branches"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:24 [
            "id" => 744411
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Некоторые сведения из планиметрии"
            "field_branch_order" => "8"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1130
              #items: array:1 [
                0 => App\Models\Term {#1047}
              ]
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "194"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1131
              #items: array:1 [
                0 => App\Models\Book {#1049}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1132
              #items: []
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 744411
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Некоторые сведения из планиметрии"
            "field_branch_order" => "8"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1130}
            "field_page_start" => "194"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1131}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1132}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        1 => App\Models\Branch {#1133
          #connection: "mysql"
          #table: "branches"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:24 [
            "id" => 744414
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Теоремы Менелая и Чевы"
            "field_branch_order" => "3"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1137
              #items: array:1 [
                0 => App\Models\Term {#1134
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:7 [
                    "id" => 32
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Параграф"
                    "field_cases" => array:6 [ …6]
                    "field_page_check_not_needed" => null
                    "field_short_name" => "§"
                  ]
                  #original: array:7 [
                    "id" => 32
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Параграф"
                    "field_cases" => array:6 [ …6]
                    "field_page_check_not_needed" => null
                    "field_short_name" => "§"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "214"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1136
              #items: array:1 [
                0 => App\Models\Book {#1049}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1135
              #items: array:1 [
                0 => App\Models\Branch {#1045}
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 744414
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Теоремы Менелая и Чевы"
            "field_branch_order" => "3"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1137}
            "field_page_start" => "214"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1136}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1135}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "content" => Illuminate\Database\Eloquent\Collection {#1038
      #items: array:4 [
        0 => App\Models\Element {#1111
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:7 [
            "id" => 940227
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1100
              #items: array:1 [
                0 => App\Models\Edition {#1108
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:21 [
                    "id" => 2315
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Условие"
                    "field_order" => "1"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1106 …2}
                    "field_content_type" => "free"
                    "field_content_mode" => "text, image"
                    "field_page_content_mode" => "image"
                    "field_content_text_checked" => null
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Автор"
                    "field_moderator" => "pasha"
                    "field_edition_type" => "statement"
                    "field_root_dir" => "0-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1107 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1105 …2}
                    "field_process_formula" => "wiris"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1104 …2}
                    "field_content_source" => null
                  ]
                  #original: array:21 [
                    "id" => 2315
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Условие"
                    "field_order" => "1"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1106 …2}
                    "field_content_type" => "free"
                    "field_content_mode" => "text, image"
                    "field_page_content_mode" => "image"
                    "field_content_text_checked" => null
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Автор"
                    "field_moderator" => "pasha"
                    "field_edition_type" => "statement"
                    "field_root_dir" => "0-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1107 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1105 …2}
                    "field_process_formula" => "wiris"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1104 …2}
                    "field_content_source" => null
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "745268"
              "type" => "task"
            ]
            "text" => "<p> <b>853.</b> На сторонах ВС, СА и АВ треугольника АВС или их продолжениях отмечены соответственно точки А₁, В₁ и С₁, лежащие на одной прямой. Докажите, что точки А₂, В₂ и С₂, симметричные соответственно точкам А₁, В₁ и С₁ относительно середин сторон ВС, СА и АВ, также лежат на одной прямой. </p>"
            "img" => array:1 [
              0 => array:5 [
                "name" => "853-1.jpg"
                "alt" => null
                "width" => "1500"
                "height" => 293
                "path" => "/media/geometrija_10/atanasjan-u23/0-00/853-1.webp?ts=1739436954"
              ]
            ]
          ]
          #original: array:7 [
            "id" => 940227
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1100}
            "task" => array:2 [
              "refs" => "745268"
              "type" => "task"
            ]
            "text" => "<p> <b>853.</b> На сторонах ВС, СА и АВ треугольника АВС или их продолжениях отмечены соответственно точки А₁, В₁ и С₁, лежащие на одной прямой. Докажите, что точки А₂, В₂ и С₂, симметричные соответственно точкам А₁, В₁ и С₁ относительно середин сторон ВС, СА и АВ, также лежат на одной прямой. </p>"
            "img" => array:1 [
              0 => array:5 [
                "name" => "853-1.jpg"
                "alt" => null
                "width" => "1500"
                "height" => 293
                "path" => "/media/geometrija_10/atanasjan-u23/0-00/853-1.webp?ts=1739436954"
              ]
            ]
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        1 => App\Models\Element {#1101
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:6 [
            "id" => 942814
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1088
              #items: array:1 [
                0 => App\Models\Edition {#1098
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:21 [
                    "id" => 2317
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 2"
                    "field_order" => "3"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1091 …2}
                    "field_content_type" => "free"
                    "field_content_mode" => "image"
                    "field_page_content_mode" => ""
                    "field_content_text_checked" => "0"
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Неизвестный"
                    "field_moderator" => "pasha"
                    "field_edition_type" => "solution"
                    "field_root_dir" => "2-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1099 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1096 …2}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1097 …2}
                    "field_content_source" => null
                  ]
                  #original: array:21 [
                    "id" => 2317
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 2"
                    "field_order" => "3"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1091 …2}
                    "field_content_type" => "free"
                    "field_content_mode" => "image"
                    "field_page_content_mode" => ""
                    "field_content_text_checked" => "0"
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Неизвестный"
                    "field_moderator" => "pasha"
                    "field_edition_type" => "solution"
                    "field_root_dir" => "2-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1099 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1096 …2}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1097 …2}
                    "field_content_source" => null
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "745268"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "853-1.png"
                "alt" => null
                "width" => "694"
                "height" => 2631
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/853-1.webp?ts=1739441758"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 942814
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1088}
            "task" => array:2 [
              "refs" => "745268"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "853-1.png"
                "alt" => null
                "width" => "694"
                "height" => 2631
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/853-1.webp?ts=1739441758"
              ]
            ]
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        2 => App\Models\Element {#1102
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:6 [
            "id" => 942547
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1093
              #items: array:1 [
                0 => App\Models\Edition {#1094
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:21 [
                    "id" => 2318
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 3"
                    "field_order" => "4"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1039 …2}
                    "field_content_type" => "free"
                    "field_content_mode" => "image"
                    "field_page_content_mode" => ""
                    "field_content_text_checked" => "0"
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Неизвестный"
                    "field_moderator" => "pasha"
                    "field_edition_type" => "solution"
                    "field_root_dir" => "3-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1043 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1090 …2}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1092 …2}
                    "field_content_source" => null
                  ]
                  #original: array:21 [
                    "id" => 2318
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 3"
                    "field_order" => "4"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1039 …2}
                    "field_content_type" => "free"
                    "field_content_mode" => "image"
                    "field_page_content_mode" => ""
                    "field_content_text_checked" => "0"
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Неизвестный"
                    "field_moderator" => "pasha"
                    "field_edition_type" => "solution"
                    "field_root_dir" => "3-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1043 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1090 …2}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1092 …2}
                    "field_content_source" => null
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "745268"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "853-1.jpg"
                "alt" => null
                "width" => "1399"
                "height" => 849
                "path" => "/media/geometrija_10/atanasjan-u23/3-00/853-1.webp?ts=1739437243"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 942547
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1093}
            "task" => array:2 [
              "refs" => "745268"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "853-1.jpg"
                "alt" => null
                "width" => "1399"
                "height" => 849
                "path" => "/media/geometrija_10/atanasjan-u23/3-00/853-1.webp?ts=1739437243"
              ]
            ]
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        3 => App\Models\Element {#1089
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:6 [
            "id" => 1352581
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1138
              #items: array:1 [
                0 => App\Models\Edition {#1087
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:21 [
                    "id" => 5120
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 6"
                    "field_order" => "7"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1120 …2}
                    "field_content_type" => "free"
                    "field_content_mode" => "text"
                    "field_page_content_mode" => ""
                    "field_content_text_checked" => null
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Gemini 2.5 Pro"
                    "field_moderator" => "vadim"
                    "field_edition_type" => "solution"
                    "field_root_dir" => "6-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1119 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1124 …2}
                    "field_process_formula" => "katex"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1122 …2}
                    "field_content_source" => null
                  ]
                  #original: array:21 [
                    "id" => 5120
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 6"
                    "field_order" => "7"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1120 …2}
                    "field_content_type" => "free"
                    "field_content_mode" => "text"
                    "field_page_content_mode" => ""
                    "field_content_text_checked" => null
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Gemini 2.5 Pro"
                    "field_moderator" => "vadim"
                    "field_edition_type" => "solution"
                    "field_root_dir" => "6-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1119 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1124 …2}
                    "field_process_formula" => "katex"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1122 …2}
                    "field_content_source" => null
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "745268"
              "type" => "task"
            ]
            "text" => "<p>Для решения задачи воспользуемся векторным методом в сочетании с теоремой Менелая.</p><p>Пусть $O$ — произвольная точка плоскости (начало координат). Обозначим радиус-векторы вершин треугольника $A, B, C$ как $\vec{a}, \vec{b}, \vec{c}$ соответственно. Пусть $M_a, M_b, M_c$ — середины сторон $BC, CA, AB$. Их радиус-векторы равны:</p><p>$\vec{m}_a = \frac{\vec{b}+\vec{c}}{2}$, $\vec{m}_b = \frac{\vec{c}+\vec{a}}{2}$, $\vec{m}_c = \frac{\vec{a}+\vec{b}}{2}$</p><p>Точка $A_1$ лежит на прямой $BC$, поэтому ее радиус-вектор $\vec{a_1}$ можно представить как аффинную комбинацию векторов $\vec{b}$ и $\vec{c}$: $\vec{a_1} = (1-t_a)\vec{b} + t_a\vec{c}$ для некоторого скалярного параметра $t_a$. Аналогично для точек $B_1$ на прямой $CA$ и $C_1$ на прямой $AB$:</p><p>$\vec{b_1} = (1-t_b)\vec{c} + t_b\vec{a}$</p><p>$\vec{c_1} = (1-t_c)\vec{a} + t_c\vec{b}$</p><p>где $t_b$ и $t_c$ — также скалярные параметры.</p><p>Точка $A_2$ симметрична точке $A_1$ относительно середины $M_a$ стороны $BC$. Это означает, что $M_a$ является серединой отрезка $A_1A_2$. В векторной форме это условие записывается как $\vec{m}_a = \frac{\vec{a_1}+\vec{a_2}}{2}$. Отсюда можно выразить радиус-вектор точки $A_2$:</p><p>$\vec{a_2} = 2\vec{m}_a - \vec{a_1} = 2 \left( \frac{\vec{b}+\vec{c}}{2} \right) - \vec{a_1} = \vec{b}+\vec{c} - \vec{a_1}$</p><p>Подставим в это равенство выражение для $\vec{a_1}$:</p><p>$\vec{a_2} = \vec{b}+\vec{c} - ((1-t_a)\vec{b} + t_a\vec{c}) = (1 - (1-t_a))\vec{b} + (1-t_a)\vec{c} = t_a\vec{b} + (1-t_a)\vec{c}$</p><p>Аналогично найдем радиус-векторы для точек $B_2$ и $C_2$:</p><p>$\vec{b_2} = 2\vec{m}_b - \vec{b_1} = \vec{c}+\vec{a} - \vec{b_1} = \vec{c}+\vec{a} - ((1-t_b)\vec{c} + t_b\vec{a}) = t_b\vec{c} + (1-t_b)\vec{a}$</p><p>$\vec{c_2} = 2\vec{m}_c - \vec{c_1} = \vec{a}+\vec{b} - \vec{c_1} = \vec{a}+\vec{b} - ((1-t_c)\vec{a} + t_c\vec{b}) = t_c\vec{a} + (1-t_c)\vec{b}$</p><p>По условию задачи, точки $A_1, B_1, C_1$ лежат на одной прямой. Согласно теореме Менелая, это эквивалентно выполнению следующего равенства для отношений, в которых эти точки делят стороны треугольника (с учетом знака, то есть для ориентированных отрезков):</p><p>$\frac{\vec{BA_1}}{\vec{A_1C}} \cdot \frac{\vec{CB_1}}{\vec{B_1A}} \cdot \frac{\vec{AC_1}}{\vec{C_1B}} = 1$</p><p>Выразим эти отношения через параметры $t_a, t_b, t_c$.</p><p>Для точки $A_1$: $\vec{BA_1} = \vec{a_1} - \vec{b} = t_a(\vec{c}-\vec{b}) = t_a\vec{BC}$ и $\vec{A_1C} = \vec{c} - \vec{a_1} = (1-t_a)(\vec{c}-\vec{b}) = (1-t_a)\vec{BC}$. Отсюда $\frac{\vec{BA_1}}{\vec{A_1C}} = \frac{t_a}{1-t_a}$.</p><p>Аналогично, для точки $B_1$: $\frac{\vec{CB_1}}{\vec{B_1A}} = \frac{t_b}{1-t_b}$.</p><p>И для точки $C_1$: $\frac{\vec{AC_1}}{\vec{C_1B}} = \frac{t_c}{1-t_c}$.</p><p>Таким образом, условие коллинеарности точек $A_1, B_1, C_1$ принимает вид:</p><p>$\frac{t_a}{1-t_a} \cdot \frac{t_b}{1-t_b} \cdot \frac{t_c}{1-t_c} = 1$</p><p>Теперь проверим, выполняется ли условие теоремы Менелая для точек $A_2, B_2, C_2$. Для этого вычислим соответствующие отношения отрезков.</p><p>Для точки $A_2$: $\vec{BA_2} = \vec{a_2}-\vec{b} = (t_a-1)\vec{b} + (1-t_a)\vec{c} = (1-t_a)(\vec{c}-\vec{b}) = (1-t_a)\vec{BC}$ и $\vec{A_2C} = \vec{c}-\vec{a_2} = -t_a\vec{b} + t_a\vec{c} = t_a(\vec{c}-\vec{b}) = t_a\vec{BC}$. Отсюда $\frac{\vec{BA_2}}{\vec{A_2C}} = \frac{1-t_a}{t_a}$.</p><p>Аналогично, для точки $B_2$: $\frac{\vec{CB_2}}{\vec{B_2A}} = \frac{1-t_b}{t_b}$.</p><p>И для точки $C_2$: $\frac{\vec{AC_2}}{\vec{C_2B}} = \frac{1-t_c}{t_c}$.</p><p>Теперь найдем произведение этих отношений:</p><p>$\frac{\vec{BA_2}}{\vec{A_2C}} \cdot \frac{\vec{CB_2}}{\vec{B_2A}} \cdot \frac{\vec{AC_2}}{\vec{C_2B}} = \frac{1-t_a}{t_a} \cdot \frac{1-t_b}{t_b} \cdot \frac{1-t_c}{t_c}$</p><p>Это произведение является обратным к произведению для точек $A_1, B_1, C_1$:</p><p>$\frac{1-t_a}{t_a} \cdot \frac{1-t_b}{t_b} \cdot \frac{1-t_c}{t_c} = \left( \frac{t_a}{1-t_a} \cdot \frac{t_b}{1-t_b} \cdot \frac{t_c}{1-t_c} \right)^{-1}$</p><p>Поскольку мы установили, что произведение для коллинеарных точек $A_1, B_1, C_1$ равно 1, то и для $A_2, B_2, C_2$ получаем:</p><p>$\left(1\right)^{-1} = 1$</p><p>Так как для точек $A_2, B_2, C_2$ выполняется условие теоремы Менелая, то по обратной теореме Менелая эти точки лежат на одной прямой. Что и требовалось доказать.</p><p>Ответ: Точки $A_2, B_2, C_2$ также лежат на одной прямой.</p>"
          ]
          #original: array:6 [
            "id" => 1352581
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1138}
            "task" => array:2 [
              "refs" => "745268"
              "type" => "task"
            ]
            "text" => "<p>Для решения задачи воспользуемся векторным методом в сочетании с теоремой Менелая.</p><p>Пусть $O$ — произвольная точка плоскости (начало координат). Обозначим радиус-векторы вершин треугольника $A, B, C$ как $\vec{a}, \vec{b}, \vec{c}$ соответственно. Пусть $M_a, M_b, M_c$ — середины сторон $BC, CA, AB$. Их радиус-векторы равны:</p><p>$\vec{m}_a = \frac{\vec{b}+\vec{c}}{2}$, $\vec{m}_b = \frac{\vec{c}+\vec{a}}{2}$, $\vec{m}_c = \frac{\vec{a}+\vec{b}}{2}$</p><p>Точка $A_1$ лежит на прямой $BC$, поэтому ее радиус-вектор $\vec{a_1}$ можно представить как аффинную комбинацию векторов $\vec{b}$ и $\vec{c}$: $\vec{a_1} = (1-t_a)\vec{b} + t_a\vec{c}$ для некоторого скалярного параметра $t_a$. Аналогично для точек $B_1$ на прямой $CA$ и $C_1$ на прямой $AB$:</p><p>$\vec{b_1} = (1-t_b)\vec{c} + t_b\vec{a}$</p><p>$\vec{c_1} = (1-t_c)\vec{a} + t_c\vec{b}$</p><p>где $t_b$ и $t_c$ — также скалярные параметры.</p><p>Точка $A_2$ симметрична точке $A_1$ относительно середины $M_a$ стороны $BC$. Это означает, что $M_a$ является серединой отрезка $A_1A_2$. В векторной форме это условие записывается как $\vec{m}_a = \frac{\vec{a_1}+\vec{a_2}}{2}$. Отсюда можно выразить радиус-вектор точки $A_2$:</p><p>$\vec{a_2} = 2\vec{m}_a - \vec{a_1} = 2 \left( \frac{\vec{b}+\vec{c}}{2} \right) - \vec{a_1} = \vec{b}+\vec{c} - \vec{a_1}$</p><p>Подставим в это равенство выражение для $\vec{a_1}$:</p><p>$\vec{a_2} = \vec{b}+\vec{c} - ((1-t_a)\vec{b} + t_a\vec{c}) = (1 - (1-t_a))\vec{b} + (1-t_a)\vec{c} = t_a\vec{b} + (1-t_a)\vec{c}$</p><p>Аналогично найдем радиус-векторы для точек $B_2$ и $C_2$:</p><p>$\vec{b_2} = 2\vec{m}_b - \vec{b_1} = \vec{c}+\vec{a} - \vec{b_1} = \vec{c}+\vec{a} - ((1-t_b)\vec{c} + t_b\vec{a}) = t_b\vec{c} + (1-t_b)\vec{a}$</p><p>$\vec{c_2} = 2\vec{m}_c - \vec{c_1} = \vec{a}+\vec{b} - \vec{c_1} = \vec{a}+\vec{b} - ((1-t_c)\vec{a} + t_c\vec{b}) = t_c\vec{a} + (1-t_c)\vec{b}$</p><p>По условию задачи, точки $A_1, B_1, C_1$ лежат на одной прямой. Согласно теореме Менелая, это эквивалентно выполнению следующего равенства для отношений, в которых эти точки делят стороны треугольника (с учетом знака, то есть для ориентированных отрезков):</p><p>$\frac{\vec{BA_1}}{\vec{A_1C}} \cdot \frac{\vec{CB_1}}{\vec{B_1A}} \cdot \frac{\vec{AC_1}}{\vec{C_1B}} = 1$</p><p>Выразим эти отношения через параметры $t_a, t_b, t_c$.</p><p>Для точки $A_1$: $\vec{BA_1} = \vec{a_1} - \vec{b} = t_a(\vec{c}-\vec{b}) = t_a\vec{BC}$ и $\vec{A_1C} = \vec{c} - \vec{a_1} = (1-t_a)(\vec{c}-\vec{b}) = (1-t_a)\vec{BC}$. Отсюда $\frac{\vec{BA_1}}{\vec{A_1C}} = \frac{t_a}{1-t_a}$.</p><p>Аналогично, для точки $B_1$: $\frac{\vec{CB_1}}{\vec{B_1A}} = \frac{t_b}{1-t_b}$.</p><p>И для точки $C_1$: $\frac{\vec{AC_1}}{\vec{C_1B}} = \frac{t_c}{1-t_c}$.</p><p>Таким образом, условие коллинеарности точек $A_1, B_1, C_1$ принимает вид:</p><p>$\frac{t_a}{1-t_a} \cdot \frac{t_b}{1-t_b} \cdot \frac{t_c}{1-t_c} = 1$</p><p>Теперь проверим, выполняется ли условие теоремы Менелая для точек $A_2, B_2, C_2$. Для этого вычислим соответствующие отношения отрезков.</p><p>Для точки $A_2$: $\vec{BA_2} = \vec{a_2}-\vec{b} = (t_a-1)\vec{b} + (1-t_a)\vec{c} = (1-t_a)(\vec{c}-\vec{b}) = (1-t_a)\vec{BC}$ и $\vec{A_2C} = \vec{c}-\vec{a_2} = -t_a\vec{b} + t_a\vec{c} = t_a(\vec{c}-\vec{b}) = t_a\vec{BC}$. Отсюда $\frac{\vec{BA_2}}{\vec{A_2C}} = \frac{1-t_a}{t_a}$.</p><p>Аналогично, для точки $B_2$: $\frac{\vec{CB_2}}{\vec{B_2A}} = \frac{1-t_b}{t_b}$.</p><p>И для точки $C_2$: $\frac{\vec{AC_2}}{\vec{C_2B}} = \frac{1-t_c}{t_c}$.</p><p>Теперь найдем произведение этих отношений:</p><p>$\frac{\vec{BA_2}}{\vec{A_2C}} \cdot \frac{\vec{CB_2}}{\vec{B_2A}} \cdot \frac{\vec{AC_2}}{\vec{C_2B}} = \frac{1-t_a}{t_a} \cdot \frac{1-t_b}{t_b} \cdot \frac{1-t_c}{t_c}$</p><p>Это произведение является обратным к произведению для точек $A_1, B_1, C_1$:</p><p>$\frac{1-t_a}{t_a} \cdot \frac{1-t_b}{t_b} \cdot \frac{1-t_c}{t_c} = \left( \frac{t_a}{1-t_a} \cdot \frac{t_b}{1-t_b} \cdot \frac{t_c}{1-t_c} \right)^{-1}$</p><p>Поскольку мы установили, что произведение для коллинеарных точек $A_1, B_1, C_1$ равно 1, то и для $A_2, B_2, C_2$ получаем:</p><p>$\left(1\right)^{-1} = 1$</p><p>Так как для точек $A_2, B_2, C_2$ выполняется условие теоремы Менелая, то по обратной теореме Менелая эти точки лежат на одной прямой. Что и требовалось доказать.</p><p>Ответ: Точки $A_2, B_2, C_2$ также лежат на одной прямой.</p>"
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "next" => array:2 [
      "refs" => "745269"
      "type" => "task"
    ]
    "previous" => array:2 [
      "refs" => "745267"
      "type" => "task"
    ]
    "book" => Illuminate\Database\Eloquent\Collection {#1112
      #items: array:1 [
        0 => App\Models\Book {#1049}
      ]
      #escapeWhenCastingToString: false
    }
    "page" => Illuminate\Database\Eloquent\Collection {#1042
      #items: array:1 [
        0 => App\Models\BookPage {#1116
          #connection: "mysql"
          #table: "book_pages"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:21 [
            "id" => 934000
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_page_start" => "218"
            "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/page-218"
            "field_display_title" => "218"
            "field_folder" => "1"
            "field_image_name" => "218"
            "field_branch_parent" => Illuminate\Database\Eloquent\Collection {#1117
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_weight" => "0"
            "field_book_parent" => Illuminate\Database\Eloquent\Collection {#1040
              #items: array:1 [
                0 => App\Models\Book {#1049}
              ]
              #escapeWhenCastingToString: false
            }
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "edition_groups" => Illuminate\Database\Eloquent\Collection {#1125
              #items: []
              #escapeWhenCastingToString: false
            }
            "content" => Illuminate\Database\Eloquent\Collection {#1147
              #items: array:1 [
                0 => App\Models\Element {#1146
                  #connection: "mysql"
                  #table: "elements"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:6 [
                    "id" => 1108264
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "edition" => Illuminate\Database\Eloquent\Collection {#1148 …2}
                    "book_page" => array:2 [ …2]
                    "img" => array:1 [ …1]
                  ]
                  #original: array:6 [
                    "id" => 1108264
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "edition" => Illuminate\Database\Eloquent\Collection {#1148 …2}
                    "book_page" => array:2 [ …2]
                    "img" => array:1 [ …1]
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "next" => array:2 [
              "refs" => "934001"
              "type" => "book_page"
            ]
            "previous" => array:2 [
              "refs" => "933999"
              "type" => "book_page"
            ]
            "tasks" => Illuminate\Database\Eloquent\Collection {#1232
              #items: array:7 [
                0 => App\Models\Task {#1246
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
                    "id" => 745266
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_page_start" => "218"
                    "field_page_end" => null
                    "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/00-851"
                    "field_display_title" => "851"
                    "field_outside_task" => null
                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1247 …2}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "field_match" => null
                    "breadcrumbs" => []
                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1248 …2}
                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1249 …2}
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1250 …2}
                    "content" => Illuminate\Database\Eloquent\Collection {#1252 …2}
                    "next" => array:2 [ …2]
                    "previous" => array:2 [ …2]
                    "book" => Illuminate\Database\Eloquent\Collection {#1261 …2}
                    "page" => array:2 [ …2]
                  ]
                  #original: array:24 [
                    "id" => 745266
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_page_start" => "218"
                    "field_page_end" => null
                    "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/00-851"
                    "field_display_title" => "851"
                    "field_outside_task" => null
                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1247 …2}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "field_match" => null
                    "breadcrumbs" => []
                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1248 …2}
                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1249 …2}
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1250 …2}
                    "content" => Illuminate\Database\Eloquent\Collection {#1252 …2}
                    "next" => array:2 [ …2]
                    "previous" => array:2 [ …2]
                    "book" => Illuminate\Database\Eloquent\Collection {#1261 …2}
                    "page" => array:2 [ …2]
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
                1 => App\Models\Task {#1253
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
                    "id" => 745267
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_page_start" => "218"
                    "field_page_end" => null
                    "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/00-852"
                    "field_display_title" => "852"
                    "field_outside_task" => null
                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1251 …2}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "field_match" => null
                    "breadcrumbs" => []
                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1259 …2}
                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1258 …2}
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1260 …2}
                    "content" => Illuminate\Database\Eloquent\Collection {#1254 …2}
                    "next" => array:2 [ …2]
                    "previous" => array:2 [ …2]
                    "book" => Illuminate\Database\Eloquent\Collection {#1277 …2}
                    "page" => array:2 [ …2]
                  ]
                  #original: array:24 [
                    "id" => 745267
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_page_start" => "218"
                    "field_page_end" => null
                    "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/00-852"
                    "field_display_title" => "852"
                    "field_outside_task" => null
                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1251 …2}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "field_match" => null
                    "breadcrumbs" => []
                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1259 …2}
                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1258 …2}
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1260 …2}
                    "content" => Illuminate\Database\Eloquent\Collection {#1254 …2}
                    "next" => array:2 [ …2]
                    "previous" => array:2 [ …2]
                    "book" => Illuminate\Database\Eloquent\Collection {#1277 …2}
                    "page" => array:2 [ …2]
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
                2 => App\Models\Task {#1257
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
                    "id" => 745268
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_page_start" => "218"
                    "field_page_end" => null
                    "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/00-853"
                    "field_display_title" => "853"
                    "field_outside_task" => null
                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1256 …2}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "field_match" => null
                    "breadcrumbs" => []
                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1275 …2}
                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1274 …2}
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1276 …2}
                    "content" => Illuminate\Database\Eloquent\Collection {#1272 …2}
                    "next" => array:2 [ …2]
                    "previous" => array:2 [ …2]
                    "book" => Illuminate\Database\Eloquent\Collection {#1255 …2}
                    "page" => array:2 [ …2]
                  ]
                  #original: array:24 [
                    "id" => 745268
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_page_start" => "218"
                    "field_page_end" => null
                    "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/00-853"
                    "field_display_title" => "853"
                    "field_outside_task" => null
                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1256 …2}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "field_match" => null
                    "breadcrumbs" => []
                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1275 …2}
                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1274 …2}
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1276 …2}
                    "content" => Illuminate\Database\Eloquent\Collection {#1272 …2}
                    "next" => array:2 [ …2]
                    "previous" => array:2 [ …2]
                    "book" => Illuminate\Database\Eloquent\Collection {#1255 …2}
                    "page" => array:2 [ …2]
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
                3 => App\Models\Task {#1273
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
                    "id" => 745269
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_page_start" => "218"
                    "field_page_end" => null
                     …19
                  ]
                  #original: array:24 [ …24]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                4 => App\Models\Task {#1292
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                5 => App\Models\Task {#1296
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                6 => App\Models\Task {#1312
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:21 [
            "id" => 934000
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_page_start" => "218"
            "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/page-218"
            "field_display_title" => "218"
            "field_folder" => "1"
            "field_image_name" => "218"
            "field_branch_parent" => Illuminate\Database\Eloquent\Collection {#1117}
            "field_weight" => "0"
            "field_book_parent" => Illuminate\Database\Eloquent\Collection {#1040}
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "edition_groups" => Illuminate\Database\Eloquent\Collection {#1125}
            "content" => Illuminate\Database\Eloquent\Collection {#1147}
            "next" => array:2 [
              "refs" => "934001"
              "type" => "book_page"
            ]
            "previous" => array:2 [
              "refs" => "933999"
              "type" => "book_page"
            ]
            "tasks" => Illuminate\Database\Eloquent\Collection {#1232}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
  ]
  #original: array:24 [
    "id" => 745268
    "created_at" => "2026-04-10 13:58:26"
    "updated_at" => null
    "field_page_start" => "218"
    "field_page_end" => null
    "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/00-853"
    "field_display_title" => "853"
    "field_outside_task" => null
    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1037}
    "field_metatags_title" => null
    "field_metatags_description" => null
    "field_h1" => null
    "field_description_top" => null
    "field_description_bottom" => null
    "field_match" => null
    "breadcrumbs" => []
    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1035}
    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1046}
    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1121}
    "content" => Illuminate\Database\Eloquent\Collection {#1038}
    "next" => array:2 [
      "refs" => "745269"
      "type" => "task"
    ]
    "previous" => array:2 [
      "refs" => "745267"
      "type" => "task"
    ]
    "book" => Illuminate\Database\Eloquent\Collection {#1112}
    "page" => array:2 [
      "refs" => "934000"
      "type" => "book_page"
    ]
  ]
  #changes: []
  #casts: []
  #classCastCache: []
  #attributeCastCache: []
  #dateFormat: null
  #appends: []
  #dispatchesEvents: []
  #observables: []
  #relations: []
  #touches: []
  +timestamps: true
  +usesUniqueIds: false
  #hidden: []
  #visible: []
  #fillable: []
  #guarded: array:1 [
    0 => "*"
  ]
}
№853 (с. 218)
Условие. №853 (с. 218)
скриншот условия
Геометрия, 10-11 класс Учебник, авторы: Атанасян Левон Сергеевич, Бутузов Валентин Фёдорович, Кадомцев Сергей Борисович, Позняк Эдуард Генрихович, Киселёва Людмила Сергеевна, издательство Просвещение, Москва, 2019, коричневого цвета, страница 218, номер 853, Условие

853. На сторонах ВС, СА и АВ треугольника АВС или их продолжениях отмечены соответственно точки А₁, В₁ и С₁, лежащие на одной прямой. Докажите, что точки А₂, В₂ и С₂, симметричные соответственно точкам А₁, В₁ и С₁ относительно середин сторон ВС, СА и АВ, также лежат на одной прямой.

Решение 2. №853 (с. 218)
Геометрия, 10-11 класс Учебник, авторы: Атанасян Левон Сергеевич, Бутузов Валентин Фёдорович, Кадомцев Сергей Борисович, Позняк Эдуард Генрихович, Киселёва Людмила Сергеевна, издательство Просвещение, Москва, 2019, коричневого цвета, страница 218, номер 853, Решение 2
Решение 3. №853 (с. 218)
Геометрия, 10-11 класс Учебник, авторы: Атанасян Левон Сергеевич, Бутузов Валентин Фёдорович, Кадомцев Сергей Борисович, Позняк Эдуард Генрихович, Киселёва Людмила Сергеевна, издательство Просвещение, Москва, 2019, коричневого цвета, страница 218, номер 853, Решение 3
Решение 6. №853 (с. 218)

Для решения задачи воспользуемся векторным методом в сочетании с теоремой Менелая.

Пусть $O$ — произвольная точка плоскости (начало координат). Обозначим радиус-векторы вершин треугольника $A, B, C$ как $\vec{a}, \vec{b}, \vec{c}$ соответственно. Пусть $M_a, M_b, M_c$ — середины сторон $BC, CA, AB$. Их радиус-векторы равны:

$\vec{m}_a = \frac{\vec{b}+\vec{c}}{2}$, $\vec{m}_b = \frac{\vec{c}+\vec{a}}{2}$, $\vec{m}_c = \frac{\vec{a}+\vec{b}}{2}$

Точка $A_1$ лежит на прямой $BC$, поэтому ее радиус-вектор $\vec{a_1}$ можно представить как аффинную комбинацию векторов $\vec{b}$ и $\vec{c}$: $\vec{a_1} = (1-t_a)\vec{b} + t_a\vec{c}$ для некоторого скалярного параметра $t_a$. Аналогично для точек $B_1$ на прямой $CA$ и $C_1$ на прямой $AB$:

$\vec{b_1} = (1-t_b)\vec{c} + t_b\vec{a}$

$\vec{c_1} = (1-t_c)\vec{a} + t_c\vec{b}$

где $t_b$ и $t_c$ — также скалярные параметры.

Точка $A_2$ симметрична точке $A_1$ относительно середины $M_a$ стороны $BC$. Это означает, что $M_a$ является серединой отрезка $A_1A_2$. В векторной форме это условие записывается как $\vec{m}_a = \frac{\vec{a_1}+\vec{a_2}}{2}$. Отсюда можно выразить радиус-вектор точки $A_2$:

$\vec{a_2} = 2\vec{m}_a - \vec{a_1} = 2 \left( \frac{\vec{b}+\vec{c}}{2} \right) - \vec{a_1} = \vec{b}+\vec{c} - \vec{a_1}$

Подставим в это равенство выражение для $\vec{a_1}$:

$\vec{a_2} = \vec{b}+\vec{c} - ((1-t_a)\vec{b} + t_a\vec{c}) = (1 - (1-t_a))\vec{b} + (1-t_a)\vec{c} = t_a\vec{b} + (1-t_a)\vec{c}$

Аналогично найдем радиус-векторы для точек $B_2$ и $C_2$:

$\vec{b_2} = 2\vec{m}_b - \vec{b_1} = \vec{c}+\vec{a} - \vec{b_1} = \vec{c}+\vec{a} - ((1-t_b)\vec{c} + t_b\vec{a}) = t_b\vec{c} + (1-t_b)\vec{a}$

$\vec{c_2} = 2\vec{m}_c - \vec{c_1} = \vec{a}+\vec{b} - \vec{c_1} = \vec{a}+\vec{b} - ((1-t_c)\vec{a} + t_c\vec{b}) = t_c\vec{a} + (1-t_c)\vec{b}$

По условию задачи, точки $A_1, B_1, C_1$ лежат на одной прямой. Согласно теореме Менелая, это эквивалентно выполнению следующего равенства для отношений, в которых эти точки делят стороны треугольника (с учетом знака, то есть для ориентированных отрезков):

$\frac{\vec{BA_1}}{\vec{A_1C}} \cdot \frac{\vec{CB_1}}{\vec{B_1A}} \cdot \frac{\vec{AC_1}}{\vec{C_1B}} = 1$

Выразим эти отношения через параметры $t_a, t_b, t_c$.

Для точки $A_1$: $\vec{BA_1} = \vec{a_1} - \vec{b} = t_a(\vec{c}-\vec{b}) = t_a\vec{BC}$ и $\vec{A_1C} = \vec{c} - \vec{a_1} = (1-t_a)(\vec{c}-\vec{b}) = (1-t_a)\vec{BC}$. Отсюда $\frac{\vec{BA_1}}{\vec{A_1C}} = \frac{t_a}{1-t_a}$.

Аналогично, для точки $B_1$: $\frac{\vec{CB_1}}{\vec{B_1A}} = \frac{t_b}{1-t_b}$.

И для точки $C_1$: $\frac{\vec{AC_1}}{\vec{C_1B}} = \frac{t_c}{1-t_c}$.

Таким образом, условие коллинеарности точек $A_1, B_1, C_1$ принимает вид:

$\frac{t_a}{1-t_a} \cdot \frac{t_b}{1-t_b} \cdot \frac{t_c}{1-t_c} = 1$

Теперь проверим, выполняется ли условие теоремы Менелая для точек $A_2, B_2, C_2$. Для этого вычислим соответствующие отношения отрезков.

Для точки $A_2$: $\vec{BA_2} = \vec{a_2}-\vec{b} = (t_a-1)\vec{b} + (1-t_a)\vec{c} = (1-t_a)(\vec{c}-\vec{b}) = (1-t_a)\vec{BC}$ и $\vec{A_2C} = \vec{c}-\vec{a_2} = -t_a\vec{b} + t_a\vec{c} = t_a(\vec{c}-\vec{b}) = t_a\vec{BC}$. Отсюда $\frac{\vec{BA_2}}{\vec{A_2C}} = \frac{1-t_a}{t_a}$.

Аналогично, для точки $B_2$: $\frac{\vec{CB_2}}{\vec{B_2A}} = \frac{1-t_b}{t_b}$.

И для точки $C_2$: $\frac{\vec{AC_2}}{\vec{C_2B}} = \frac{1-t_c}{t_c}$.

Теперь найдем произведение этих отношений:

$\frac{\vec{BA_2}}{\vec{A_2C}} \cdot \frac{\vec{CB_2}}{\vec{B_2A}} \cdot \frac{\vec{AC_2}}{\vec{C_2B}} = \frac{1-t_a}{t_a} \cdot \frac{1-t_b}{t_b} \cdot \frac{1-t_c}{t_c}$

Это произведение является обратным к произведению для точек $A_1, B_1, C_1$:

$\frac{1-t_a}{t_a} \cdot \frac{1-t_b}{t_b} \cdot \frac{1-t_c}{t_c} = \left( \frac{t_a}{1-t_a} \cdot \frac{t_b}{1-t_b} \cdot \frac{t_c}{1-t_c} \right)^{-1}$

Поскольку мы установили, что произведение для коллинеарных точек $A_1, B_1, C_1$ равно 1, то и для $A_2, B_2, C_2$ получаем:

$\left(1\right)^{-1} = 1$

Так как для точек $A_2, B_2, C_2$ выполняется условие теоремы Менелая, то по обратной теореме Менелая эти точки лежат на одной прямой. Что и требовалось доказать.

Ответ: Точки $A_2, B_2, C_2$ также лежат на одной прямой.

Помогло решение? Оставьте отзыв в комментариях ниже.

Присоединяйтесь к Телеграм-группе @top_gdz

Присоединиться

Мы подготовили для вас ответ c подробным объяснением домашего задания по геометрии за 10-11 класс, для упражнения номер 853 расположенного на странице 218 к учебнику 2019 года издания для учащихся школ и гимназий.

Теперь на нашем сайте ГДЗ.ТОП вы всегда легко и бесплатно найдёте условие с правильным ответом на вопрос «Как решить ДЗ» и «Как сделать» задание по геометрии к упражнению №853 (с. 218), авторов: Атанасян (Левон Сергеевич), Бутузов (Валентин Фёдорович), Кадомцев (Сергей Борисович), Позняк (Эдуард Генрихович), Киселёва (Людмила Сергеевна), ФГОС (старый) базовый и углублённый уровень обучения учебного пособия издательства Просвещение.