Номер 254, страница 77 - 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 3. Многогранники. Параграф 2. Пирамида - номер 254, страница 77.

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" => 744669
    "created_at" => "2026-04-10 13:58:26"
    "updated_at" => null
    "field_page_start" => "77"
    "field_page_end" => null
    "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/00-254"
    "field_display_title" => "254"
    "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" => 744380
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Многогранники"
            "field_branch_order" => "3"
            "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" => "63"
            "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 [ …10]
                          #original: array:10 [ …10]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #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 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                        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 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #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 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #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 [ …12]
                          #original: array:12 [ …12]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                        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 [ …12]
                          #original: array:12 [ …12]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                        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 [ …12]
                          #original: array:12 [ …12]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                        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 [ …12]
                          #original: array:12 [ …12]
                          #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\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 [ …12]
                          #original: array:12 [ …12]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #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 [ …10]
                          #original: array:10 [ …10]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #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 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #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 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #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 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #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 [ …10]
                          #original: array:10 [ …10]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #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 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #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 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #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" => 744380
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Многогранники"
            "field_branch_order" => "3"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1050}
            "field_page_start" => "63"
            "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" => 744380
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Многогранники"
            "field_branch_order" => "3"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1130
              #items: array:1 [
                0 => App\Models\Term {#1047}
              ]
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "63"
            "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" => 744380
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Многогранники"
            "field_branch_order" => "3"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1130}
            "field_page_start" => "63"
            "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" => 744382
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Пирамида"
            "field_branch_order" => "2"
            "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" => "72"
            "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" => 744382
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Пирамида"
            "field_branch_order" => "2"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1137}
            "field_page_start" => "72"
            "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:6 [
        0 => App\Models\Element {#1109
          #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" => 938903
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1098
              #items: array:1 [
                0 => App\Models\Edition {#1106
                  #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 {#1105 …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 {#1104 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1102 …2}
                    "field_process_formula" => "wiris"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1103 …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 {#1105 …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 {#1104 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1102 …2}
                    "field_process_formula" => "wiris"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1103 …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" => "744669"
              "type" => "task"
            ]
            "text" => "<p> <b>254.</b> В правильной треугольной пирамиде сторона основания равна <i>а</i>, высота равна <i>Н</i>. Найдите: а) боковое ребро пирамиды; б) плоский угол при вершине пирамиды; в) угол между боковым ребром и плоскостью основания пирамиды; г) угол между боковой гранью и основанием пирамиды; д) двугранный угол при боковом ребре пирамиды . </p>"
            "img" => array:1 [
              0 => array:5 [
                "name" => "254-1.jpg"
                "alt" => null
                "width" => "1545"
                "height" => 335
                "path" => "/media/geometrija_10/atanasjan-u23/0-00/254-1.webp?ts=1739436493"
              ]
            ]
          ]
          #original: array:7 [
            "id" => 938903
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1098}
            "task" => array:2 [
              "refs" => "744669"
              "type" => "task"
            ]
            "text" => "<p> <b>254.</b> В правильной треугольной пирамиде сторона основания равна <i>а</i>, высота равна <i>Н</i>. Найдите: а) боковое ребро пирамиды; б) плоский угол при вершине пирамиды; в) угол между боковым ребром и плоскостью основания пирамиды; г) угол между боковой гранью и основанием пирамиды; д) двугранный угол при боковом ребре пирамиды . </p>"
            "img" => array:1 [
              0 => array:5 [
                "name" => "254-1.jpg"
                "alt" => null
                "width" => "1545"
                "height" => 335
                "path" => "/media/geometrija_10/atanasjan-u23/0-00/254-1.webp?ts=1739436493"
              ]
            ]
          ]
          #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 {#1122
          #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" => 940825
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1145
              #items: array:1 [
                0 => App\Models\Edition {#1125
                  #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 {#1139 …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 {#1140 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1141 …2}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1142 …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 {#1139 …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 {#1140 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1141 …2}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1142 …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" => "744669"
              "type" => "task"
            ]
            "img" => array:5 [
              0 => array:5 [
                "name" => "254-1.png"
                "alt" => null
                "width" => "694"
                "height" => 2105
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/254-1.webp?ts=1739441107"
              ]
              1 => array:5 [
                "name" => "254-2.png"
                "alt" => null
                "width" => "694"
                "height" => 3505
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/254-2.webp?ts=1739441107"
              ]
              2 => array:5 [
                "name" => "254-3.png"
                "alt" => null
                "width" => "694"
                "height" => 2366
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/254-3.webp?ts=1739441107"
              ]
              3 => array:5 [
                "name" => "254-4.png"
                "alt" => null
                "width" => "694"
                "height" => 2409
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/254-4.webp?ts=1739441107"
              ]
              4 => array:5 [
                "name" => "254-5.png"
                "alt" => null
                "width" => "694"
                "height" => 5979
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/254-5.webp?ts=1739441107"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 940825
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1145}
            "task" => array:2 [
              "refs" => "744669"
              "type" => "task"
            ]
            "img" => array:5 [
              0 => array:5 [
                "name" => "254-1.png"
                "alt" => null
                "width" => "694"
                "height" => 2105
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/254-1.webp?ts=1739441107"
              ]
              1 => array:5 [
                "name" => "254-2.png"
                "alt" => null
                "width" => "694"
                "height" => 3505
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/254-2.webp?ts=1739441107"
              ]
              2 => array:5 [
                "name" => "254-3.png"
                "alt" => null
                "width" => "694"
                "height" => 2366
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/254-3.webp?ts=1739441107"
              ]
              3 => array:5 [
                "name" => "254-4.png"
                "alt" => null
                "width" => "694"
                "height" => 2409
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/254-4.webp?ts=1739441107"
              ]
              4 => array:5 [
                "name" => "254-5.png"
                "alt" => null
                "width" => "694"
                "height" => 5979
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/254-5.webp?ts=1739441107"
              ]
            ]
          ]
          #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 {#1100
          #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" => 940569
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1092
              #items: array:1 [
                0 => App\Models\Edition {#1101
                  #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 {#1097 …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 {#1091 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1096 …2}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1095 …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 {#1097 …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 {#1091 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1096 …2}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1095 …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" => "744669"
              "type" => "task"
            ]
            "img" => array:3 [
              0 => array:5 [
                "name" => "254-1.jpg"
                "alt" => null
                "width" => "1300"
                "height" => 1778
                "path" => "/media/geometrija_10/atanasjan-u23/3-00/254-1.webp?ts=1739436698"
              ]
              1 => array:5 [
                "name" => "254-2.jpg"
                "alt" => null
                "width" => "1300"
                "height" => 2037
                "path" => "/media/geometrija_10/atanasjan-u23/3-00/254-2.webp?ts=1739436698"
              ]
              2 => array:5 [
                "name" => "254-3.jpg"
                "alt" => null
                "width" => "1300"
                "height" => 1324
                "path" => "/media/geometrija_10/atanasjan-u23/3-00/254-3.webp?ts=1739436698"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 940569
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1092}
            "task" => array:2 [
              "refs" => "744669"
              "type" => "task"
            ]
            "img" => array:3 [
              0 => array:5 [
                "name" => "254-1.jpg"
                "alt" => null
                "width" => "1300"
                "height" => 1778
                "path" => "/media/geometrija_10/atanasjan-u23/3-00/254-1.webp?ts=1739436698"
              ]
              1 => array:5 [
                "name" => "254-2.jpg"
                "alt" => null
                "width" => "1300"
                "height" => 2037
                "path" => "/media/geometrija_10/atanasjan-u23/3-00/254-2.webp?ts=1739436698"
              ]
              2 => array:5 [
                "name" => "254-3.jpg"
                "alt" => null
                "width" => "1300"
                "height" => 1324
                "path" => "/media/geometrija_10/atanasjan-u23/3-00/254-3.webp?ts=1739436698"
              ]
            ]
          ]
          #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 {#1094
          #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" => 940625
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1034
              #items: array:1 [
                0 => App\Models\Edition {#1093
                  #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" => 2319
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 4"
                    "field_order" => "5"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1090 …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" => "4-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1085 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1088 …2}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1087 …2}
                    "field_content_source" => null
                  ]
                  #original: array:21 [
                    "id" => 2319
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 4"
                    "field_order" => "5"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1090 …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" => "4-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1085 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1088 …2}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1087 …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" => "744669"
              "type" => "task"
            ]
            "img" => array:2 [
              0 => array:5 [
                "name" => "254-1.jpg"
                "alt" => null
                "width" => "1148"
                "height" => 1146
                "path" => "/media/geometrija_10/atanasjan-u23/4-00/254-1.webp?ts=1739436477"
              ]
              1 => array:5 [
                "name" => "254-2.jpg"
                "alt" => null
                "width" => "1148"
                "height" => 1502
                "path" => "/media/geometrija_10/atanasjan-u23/4-00/254-2.webp?ts=1739436477"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 940625
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1034}
            "task" => array:2 [
              "refs" => "744669"
              "type" => "task"
            ]
            "img" => array:2 [
              0 => array:5 [
                "name" => "254-1.jpg"
                "alt" => null
                "width" => "1148"
                "height" => 1146
                "path" => "/media/geometrija_10/atanasjan-u23/4-00/254-1.webp?ts=1739436477"
              ]
              1 => array:5 [
                "name" => "254-2.jpg"
                "alt" => null
                "width" => "1148"
                "height" => 1502
                "path" => "/media/geometrija_10/atanasjan-u23/4-00/254-2.webp?ts=1739436477"
              ]
            ]
          ]
          #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\Element {#1043
          #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" => 940792
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1123
              #items: array:1 [
                0 => App\Models\Edition {#1041
                  #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" => 2320
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 5"
                    "field_order" => "6"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1120 …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" => "5-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1119 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1128 …2}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1124 …2}
                    "field_content_source" => null
                  ]
                  #original: array:21 [
                    "id" => 2320
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 5"
                    "field_order" => "6"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1120 …2}
                    "field_content_type" => "free"
                    "field_content_mode" => "image"
                    "field_page_content_mode" => ""
                    "field_content_text_checked" => "0"
                    "field_page_content_text_checked" => "0"
                     …10
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "744669"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "254-1.jpg"
                "alt" => null
                "width" => "582"
                "height" => 906
                "path" => "/media/geometrija_10/atanasjan-u23/5-00/254-1.webp?ts=1739436519"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 940792
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1123}
            "task" => array:2 [
              "refs" => "744669"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "254-1.jpg"
                "alt" => null
                "width" => "582"
                "height" => 906
                "path" => "/media/geometrija_10/atanasjan-u23/5-00/254-1.webp?ts=1739436519"
              ]
            ]
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        5 => App\Models\Element {#1143
          #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" => 1351982
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1153
              #items: array:1 [
                0 => App\Models\Edition {#1144
                  #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 [ …21]
                  #original: array:21 [ …21]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "744669"
              "type" => "task"
            ]
            "text" => "<p>Пусть дана правильная треугольная пирамида <span>SABC</span>, где <span>S</span> — вершина, а <span>ABC</span> — равносторонний треугольник в основании со стороной <span>a</span>. <span>SO = H</span> — высота пирамиды, где <span>O</span> — центр основания (точка пересечения медиан, высот и биссектрис).</p><p>Для решения задачи нам понадобятся некоторые размеры в основании. <span>O</span> — центр описанной и вписанной окружностей для треугольника <span>ABC</span>.</p><p>Радиус описанной окружности <span>R</span> (отрезок <span>OA</span>) для равностороннего треугольника со стороной <span>a</span> равен:$R = OA = \frac{a}{\sqrt{3}}$</p><p>Радиус вписанной окружности <span>r</span> (длина перпендикуляра из <span>O</span> к стороне, например, <span>OM</span>, где <span>M</span> — середина <span>BC</span>) равен:$r = OM = \frac{a}{2\sqrt{3}}$</p><p><strong>а) боковое ребро пирамиды</strong></p><p>Боковое ребро, обозначим его <span>l</span> (например, <span>SA</span>), является гипотенузой в прямоугольном треугольнике <span>SOA</span>. Катеты этого треугольника — высота пирамиды <span>SO = H</span> и радиус описанной окружности основания <span>OA = R</span>.</p><p>По теореме Пифагора:$l^2 = SA^2 = SO^2 + OA^2 = H^2 + R^2$</p><p>Подставим значение <span>R</span>:$l^2 = H^2 + \left(\frac{a}{\sqrt{3}}\right)^2 = H^2 + \frac{a^2}{3}$</p><p>Отсюда длина бокового ребра:$l = \sqrt{H^2 + \frac{a^2}{3}}$</p><p>Ответ: $l = \sqrt{H^2 + \frac{a^2}{3}}$</p><p><strong>б) плоский угол при вершине пирамиды</strong></p><p>Плоский угол при вершине — это угол в боковой грани, например, угол <span>? = ?BSC</span>. Боковая грань (например, треугольник <span>SBC</span>) — равнобедренный треугольник с боковыми сторонами <span>SB = SC = l</span> и основанием <span>BC = a</span>.</p><p>Проведем в треугольнике <span>SBC</span> высоту (она же медиана и биссектриса) <span>SM</span> к основанию <span>BC</span>. <span>M</span> — середина <span>BC</span>, поэтому <span>BM = a/2</span>.</p><p>В прямоугольном треугольнике <span>SMB</span> угол <span>?BSM = ?/2</span>. Из определения синуса:$\sin\left(\frac{\alpha}{2}\right) = \frac{BM}{SB} = \frac{a/2}{l} = \frac{a}{2l}$</p><p>Подставим найденное ранее выражение для <span>l</span>:$\sin\left(\frac{\alpha}{2}\right) = \frac{a}{2\sqrt{H^2 + a^2/3}}$</p><p>Тогда искомый угол <span>?</span>:$\alpha = 2\arcsin\left(\frac{a}{2\sqrt{H^2 + a^2/3}}\right)$</p><p>Ответ: $\alpha = 2\arcsin\left(\frac{a}{2\sqrt{H^2 + a^2/3}}\right)$</p><p><strong>в) угол между боковым ребром и плоскостью основания пирамиды</strong></p><p>Угол между боковым ребром (например, <span>SA</span>) и плоскостью основания <span>ABC</span> — это угол между ребром <span>SA</span> и его проекцией на плоскость основания, которой является отрезок <span>OA</span>. Обозначим этот угол <span>? = ?SAO</span>.</p><p>Рассмотрим прямоугольный треугольник <span>SOA</span>.$\tan(\beta) = \frac{SO}{OA} = \frac{H}{R} = \frac{H}{a/\sqrt{3}} = \frac{H\sqrt{3}}{a}$</p><p>Отсюда угол <span>?</span>:$\beta = \arctan\left(\frac{H\sqrt{3}}{a}\right)$</p><p>Ответ: $\beta = \arctan\left(\frac{H\sqrt{3}}{a}\right)$</p><p><strong>г) угол между боковой гранью и основанием пирамиды</strong></p><p>Угол между боковой гранью (например, <span>SBC</span>) и основанием <span>ABC</span> — это линейный угол двугранного угла при ребре <span>BC</span>.</p><p>Проведем апофему <span>SM</span> (<span>M</span> — середина <span>BC</span>). Так как <span>SBC</span> — равнобедренный треугольник, <span>SM ? BC</span>. В основании <span>AM</span> — медиана и высота, поэтому <span>AM ? BC</span>. Следовательно, искомый угол <span>?</span> — это угол <span>?SMA</span>. Так как точка <span>O</span> лежит на <span>AM</span>, это угол <span>?SMO</span>.</p><p>Рассмотрим прямоугольный треугольник <span>SOM</span>.$\tan(\gamma) = \frac{SO}{OM} = \frac{H}{r} = \frac{H}{a/(2\sqrt{3})} = \frac{2H\sqrt{3}}{a}$</p><p>Отсюда угол <span>?</span>:$\gamma = \arctan\left(\frac{2H\sqrt{3}}{a}\right)$</p><p>Ответ: $\gamma = \arctan\left(\frac{2H\sqrt{3}}{a}\right)$</p><p><strong>д) двугранный угол при боковом ребре пирамиды</strong></p><p>Двугранный угол при боковом ребре (например, <span>SA</span>) — это угол <span>?</span> между плоскостями боковых граней <span>SAB</span> и <span>SAC</span>.</p><p>Для нахождения этого угла построим его линейный угол. Проведем в грани <span>SAB</span> перпендикуляр <span>BK</span> к ребру <span>SA</span>. Так как боковые грани <span>SAB</span> и <span>SAC</span> равны, то перпендикуляр из точки <span>C</span> к ребру <span>SA</span> также придет в точку <span>K</span>, то есть <span>CK ? SA</span>.</p><p>Тогда искомый угол <span>? = ?BKC</span>. Треугольник <span>BKC</span> — равнобедренный с основанием <span>BC = a</span> и равными сторонами <span>BK = CK</span>.</p><p>По теореме косинусов для треугольника <span>BKC</span>:$BC^2 = BK^2 + CK^2 - 2 \cdot BK \cdot CK \cdot \cos(\delta) \implies a^2 = 2BK^2(1 - \cos\delta)$$\cos(\delta) = 1 - \frac{a^2}{2BK^2}$</p><p>Найдем длину <span>BK</span>. Площадь треугольника <span>SAB</span> можно выразить двумя способами:$S_{\triangle SAB} = \frac{1}{2} AB \cdot SM = \frac{1}{2} SA \cdot BK \implies a \cdot SM = l \cdot BK \implies BK = \frac{a \cdot SM}{l}$</p><p>Найдем квадраты длин <span>SM</span> и <span>l</span>.Из прямоугольного треугольника <span>SOM</span>: $SM^2 = SO^2 + OM^2 = H^2 + r^2 = H^2 + \left(\frac{a}{2\sqrt{3}}\right)^2 = H^2 + \frac{a^2}{12}$.Длина бокового ребра: $l^2 = H^2 + \frac{a^2}{3}$.</p><p>Теперь найдем $BK^2$:$BK^2 = \frac{a^2 \cdot SM^2}{l^2} = \frac{a^2 \left(H^2 + \frac{a^2}{12}\right)}{H^2 + \frac{a^2}{3}} = \frac{a^2 \frac{12H^2 + a^2}{12}}{\frac{3H^2 + a^2}{3}} = \frac{a^2 (12H^2 + a^2)}{4(3H^2 + a^2)}$</p><p>Подставим <span>BK?</span> в формулу для косинуса угла <span>?</span>:$\cos(\delta) = 1 - \frac{a^2}{2 \cdot \frac{a^2(12H^2+a^2)}{4(3H^2+a^2)}} = 1 - \frac{2(3H^2+a^2)}{12H^2+a^2}$</p><p>$\cos(\delta) = \frac{(12H^2+a^2) - (6H^2+2a^2)}{12H^2+a^2} = \frac{6H^2 - a^2}{12H^2 + a^2}$</p><p>Отсюда угол <span>?</span>:$\delta = \arccos\left(\frac{6H^2 - a^2}{12H^2 + a^2}\right)$</p><p>Ответ: $\delta = \arccos\left(\frac{6H^2 - a^2}{12H^2 + a^2}\right)$</p>"
          ]
          #original: array:6 [
            "id" => 1351982
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1153}
            "task" => array:2 [
              "refs" => "744669"
              "type" => "task"
            ]
            "text" => "<p>Пусть дана правильная треугольная пирамида <span>SABC</span>, где <span>S</span> — вершина, а <span>ABC</span> — равносторонний треугольник в основании со стороной <span>a</span>. <span>SO = H</span> — высота пирамиды, где <span>O</span> — центр основания (точка пересечения медиан, высот и биссектрис).</p><p>Для решения задачи нам понадобятся некоторые размеры в основании. <span>O</span> — центр описанной и вписанной окружностей для треугольника <span>ABC</span>.</p><p>Радиус описанной окружности <span>R</span> (отрезок <span>OA</span>) для равностороннего треугольника со стороной <span>a</span> равен:$R = OA = \frac{a}{\sqrt{3}}$</p><p>Радиус вписанной окружности <span>r</span> (длина перпендикуляра из <span>O</span> к стороне, например, <span>OM</span>, где <span>M</span> — середина <span>BC</span>) равен:$r = OM = \frac{a}{2\sqrt{3}}$</p><p><strong>а) боковое ребро пирамиды</strong></p><p>Боковое ребро, обозначим его <span>l</span> (например, <span>SA</span>), является гипотенузой в прямоугольном треугольнике <span>SOA</span>. Катеты этого треугольника — высота пирамиды <span>SO = H</span> и радиус описанной окружности основания <span>OA = R</span>.</p><p>По теореме Пифагора:$l^2 = SA^2 = SO^2 + OA^2 = H^2 + R^2$</p><p>Подставим значение <span>R</span>:$l^2 = H^2 + \left(\frac{a}{\sqrt{3}}\right)^2 = H^2 + \frac{a^2}{3}$</p><p>Отсюда длина бокового ребра:$l = \sqrt{H^2 + \frac{a^2}{3}}$</p><p>Ответ: $l = \sqrt{H^2 + \frac{a^2}{3}}$</p><p><strong>б) плоский угол при вершине пирамиды</strong></p><p>Плоский угол при вершине — это угол в боковой грани, например, угол <span>? = ?BSC</span>. Боковая грань (например, треугольник <span>SBC</span>) — равнобедренный треугольник с боковыми сторонами <span>SB = SC = l</span> и основанием <span>BC = a</span>.</p><p>Проведем в треугольнике <span>SBC</span> высоту (она же медиана и биссектриса) <span>SM</span> к основанию <span>BC</span>. <span>M</span> — середина <span>BC</span>, поэтому <span>BM = a/2</span>.</p><p>В прямоугольном треугольнике <span>SMB</span> угол <span>?BSM = ?/2</span>. Из определения синуса:$\sin\left(\frac{\alpha}{2}\right) = \frac{BM}{SB} = \frac{a/2}{l} = \frac{a}{2l}$</p><p>Подставим найденное ранее выражение для <span>l</span>:$\sin\left(\frac{\alpha}{2}\right) = \frac{a}{2\sqrt{H^2 + a^2/3}}$</p><p>Тогда искомый угол <span>?</span>:$\alpha = 2\arcsin\left(\frac{a}{2\sqrt{H^2 + a^2/3}}\right)$</p><p>Ответ: $\alpha = 2\arcsin\left(\frac{a}{2\sqrt{H^2 + a^2/3}}\right)$</p><p><strong>в) угол между боковым ребром и плоскостью основания пирамиды</strong></p><p>Угол между боковым ребром (например, <span>SA</span>) и плоскостью основания <span>ABC</span> — это угол между ребром <span>SA</span> и его проекцией на плоскость основания, которой является отрезок <span>OA</span>. Обозначим этот угол <span>? = ?SAO</span>.</p><p>Рассмотрим прямоугольный треугольник <span>SOA</span>.$\tan(\beta) = \frac{SO}{OA} = \frac{H}{R} = \frac{H}{a/\sqrt{3}} = \frac{H\sqrt{3}}{a}$</p><p>Отсюда угол <span>?</span>:$\beta = \arctan\left(\frac{H\sqrt{3}}{a}\right)$</p><p>Ответ: $\beta = \arctan\left(\frac{H\sqrt{3}}{a}\right)$</p><p><strong>г) угол между боковой гранью и основанием пирамиды</strong></p><p>Угол между боковой гранью (например, <span>SBC</span>) и основанием <span>ABC</span> — это линейный угол двугранного угла при ребре <span>BC</span>.</p><p>Проведем апофему <span>SM</span> (<span>M</span> — середина <span>BC</span>). Так как <span>SBC</span> — равнобедренный треугольник, <span>SM ? BC</span>. В основании <span>AM</span> — медиана и высота, поэтому <span>AM ? BC</span>. Следовательно, искомый угол <span>?</span> — это угол <span>?SMA</span>. Так как точка <span>O</span> лежит на <span>AM</span>, это угол <span>?SMO</span>.</p><p>Рассмотрим прямоугольный треугольник <span>SOM</span>.$\tan(\gamma) = \frac{SO}{OM} = \frac{H}{r} = \frac{H}{a/(2\sqrt{3})} = \frac{2H\sqrt{3}}{a}$</p><p>Отсюда угол <span>?</span>:$\gamma = \arctan\left(\frac{2H\sqrt{3}}{a}\right)$</p><p>Ответ: $\gamma = \arctan\left(\frac{2H\sqrt{3}}{a}\right)$</p><p><strong>д) двугранный угол при боковом ребре пирамиды</strong></p><p>Двугранный угол при боковом ребре (например, <span>SA</span>) — это угол <span>?</span> между плоскостями боковых граней <span>SAB</span> и <span>SAC</span>.</p><p>Для нахождения этого угла построим его линейный угол. Проведем в грани <span>SAB</span> перпендикуляр <span>BK</span> к ребру <span>SA</span>. Так как боковые грани <span>SAB</span> и <span>SAC</span> равны, то перпендикуляр из точки <span>C</span> к ребру <span>SA</span> также придет в точку <span>K</span>, то есть <span>CK ? SA</span>.</p><p>Тогда искомый угол <span>? = ?BKC</span>. Треугольник <span>BKC</span> — равнобедренный с основанием <span>BC = a</span> и равными сторонами <span>BK = CK</span>.</p><p>По теореме косинусов для треугольника <span>BKC</span>:$BC^2 = BK^2 + CK^2 - 2 \cdot BK \cdot CK \cdot \cos(\delta) \implies a^2 = 2BK^2(1 - \cos\delta)$$\cos(\delta) = 1 - \frac{a^2}{2BK^2}$</p><p>Найдем длину <span>BK</span>. Площадь треугольника <span>SAB</span> можно выразить двумя способами:$S_{\triangle SAB} = \frac{1}{2} AB \cdot SM = \frac{1}{2} SA \cdot BK \implies a \cdot SM = l \cdot BK \implies BK = \frac{a \cdot SM}{l}$</p><p>Найдем квадраты длин <span>SM</span> и <span>l</span>.Из прямоугольного треугольника <span>SOM</span>: $SM^2 = SO^2 + OM^2 = H^2 + r^2 = H^2 + \left(\frac{a}{2\sqrt{3}}\right)^2 = H^2 + \frac{a^2}{12}$.Длина бокового ребра: $l^2 = H^2 + \frac{a^2}{3}$.</p><p>Теперь найдем $BK^2$:$BK^2 = \frac{a^2 \cdot SM^2}{l^2} = \frac{a^2 \left(H^2 + \frac{a^2}{12}\right)}{H^2 + \frac{a^2}{3}} = \frac{a^2 \frac{12H^2 + a^2}{12}}{\frac{3H^2 + a^2}{3}} = \frac{a^2 (12H^2 + a^2)}{4(3H^2 + a^2)}$</p><p>Подставим <span>BK?</span> в формулу для косинуса угла <span>?</span>:$\cos(\delta) = 1 - \frac{a^2}{2 \cdot \frac{a^2(12H^2+a^2)}{4(3H^2+a^2)}} = 1 - \frac{2(3H^2+a^2)}{12H^2+a^2}$</p><p>$\cos(\delta) = \frac{(12H^2+a^2) - (6H^2+2a^2)}{12H^2+a^2} = \frac{6H^2 - a^2}{12H^2 + a^2}$</p><p>Отсюда угол <span>?</span>:$\delta = \arccos\left(\frac{6H^2 - a^2}{12H^2 + a^2}\right)$</p><p>Ответ: $\delta = \arccos\left(\frac{6H^2 - a^2}{12H^2 + a^2}\right)$</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" => "744670"
      "type" => "task"
    ]
    "previous" => array:2 [
      "refs" => "744668"
      "type" => "task"
    ]
    "book" => Illuminate\Database\Eloquent\Collection {#1111
      #items: array:1 [
        0 => App\Models\Book {#1049}
      ]
      #escapeWhenCastingToString: false
    }
    "page" => Illuminate\Database\Eloquent\Collection {#1113
      #items: array:1 [
        0 => App\Models\BookPage {#1115
          #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" => 933859
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_page_start" => "77"
            "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/page-77"
            "field_display_title" => "77"
            "field_folder" => "1"
            "field_image_name" => "77"
            "field_branch_parent" => Illuminate\Database\Eloquent\Collection {#1116
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_weight" => "0"
            "field_book_parent" => Illuminate\Database\Eloquent\Collection {#1042
              #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 {#1117
              #items: []
              #escapeWhenCastingToString: false
            }
            "content" => Illuminate\Database\Eloquent\Collection {#1160
              #items: array:1 [
                0 => App\Models\Element {#1159
                  #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 [ …6]
                  #original: array:6 [ …6]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "next" => array:2 [
              "refs" => "933860"
              "type" => "book_page"
            ]
            "previous" => array:2 [
              "refs" => "933858"
              "type" => "book_page"
            ]
            "tasks" => Illuminate\Database\Eloquent\Collection {#1262
              #items: array:12 [
                0 => App\Models\Task {#1280
                  #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]
                }
                1 => App\Models\Task {#1287
                  #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]
                }
                2 => App\Models\Task {#1290
                  #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]
                }
                3 => App\Models\Task {#1314
                  #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]
                }
                4 => App\Models\Task {#1317
                  #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 {#1316
                  #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 {#1318
                  #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]
                }
                7 => App\Models\Task {#1338
                  #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]
                }
                8 => App\Models\Task {#1358
                  #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]
                }
                9 => App\Models\Task {#1378
                  #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]
                }
                10 => App\Models\Task {#1398
                  #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]
                }
                11 => App\Models\Task {#1418
                  #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" => 933859
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_page_start" => "77"
            "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/page-77"
            "field_display_title" => "77"
            "field_folder" => "1"
            "field_image_name" => "77"
            "field_branch_parent" => Illuminate\Database\Eloquent\Collection {#1116}
            "field_weight" => "0"
            "field_book_parent" => Illuminate\Database\Eloquent\Collection {#1042}
            "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 {#1117}
            "content" => Illuminate\Database\Eloquent\Collection {#1160}
            "next" => array:2 [
              "refs" => "933860"
              "type" => "book_page"
            ]
            "previous" => array:2 [
              "refs" => "933858"
              "type" => "book_page"
            ]
            "tasks" => Illuminate\Database\Eloquent\Collection {#1262}
          ]
          #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" => 744669
    "created_at" => "2026-04-10 13:58:26"
    "updated_at" => null
    "field_page_start" => "77"
    "field_page_end" => null
    "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/00-254"
    "field_display_title" => "254"
    "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" => "744670"
      "type" => "task"
    ]
    "previous" => array:2 [
      "refs" => "744668"
      "type" => "task"
    ]
    "book" => Illuminate\Database\Eloquent\Collection {#1111}
    "page" => array:2 [
      "refs" => "933859"
      "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 => "*"
  ]
}
№254 (с. 77)
Условие. №254 (с. 77)
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 77, номер 254, Условие

254. В правильной треугольной пирамиде сторона основания равна а, высота равна Н. Найдите: а) боковое ребро пирамиды; б) плоский угол при вершине пирамиды; в) угол между боковым ребром и плоскостью основания пирамиды; г) угол между боковой гранью и основанием пирамиды; д) двугранный угол при боковом ребре пирамиды .

Решение 2. №254 (с. 77)
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 77, номер 254, Решение 2
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 77, номер 254, Решение 2 (продолжение 2)
Решение 3. №254 (с. 77)
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 77, номер 254, Решение 3
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 77, номер 254, Решение 3 (продолжение 2)
Решение 4. №254 (с. 77)
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 77, номер 254, Решение 4
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 77, номер 254, Решение 4 (продолжение 2)
Решение 5. №254 (с. 77)
Решение 6. №254 (с. 77)

Пусть дана правильная треугольная пирамида SABC, где S — вершина, а ABC — равносторонний треугольник в основании со стороной a. SO = H — высота пирамиды, где O — центр основания (точка пересечения медиан, высот и биссектрис).

Для решения задачи нам понадобятся некоторые размеры в основании. O — центр описанной и вписанной окружностей для треугольника ABC.

Радиус описанной окружности R (отрезок OA) для равностороннего треугольника со стороной a равен:$R = OA = \frac{a}{\sqrt{3}}$

Радиус вписанной окружности r (длина перпендикуляра из O к стороне, например, OM, где M — середина BC) равен:$r = OM = \frac{a}{2\sqrt{3}}$

а) боковое ребро пирамиды

Боковое ребро, обозначим его l (например, SA), является гипотенузой в прямоугольном треугольнике SOA. Катеты этого треугольника — высота пирамиды SO = H и радиус описанной окружности основания OA = R.

По теореме Пифагора:$l^2 = SA^2 = SO^2 + OA^2 = H^2 + R^2$

Подставим значение R:$l^2 = H^2 + \left(\frac{a}{\sqrt{3}}\right)^2 = H^2 + \frac{a^2}{3}$

Отсюда длина бокового ребра:$l = \sqrt{H^2 + \frac{a^2}{3}}$

Ответ: $l = \sqrt{H^2 + \frac{a^2}{3}}$

б) плоский угол при вершине пирамиды

Плоский угол при вершине — это угол в боковой грани, например, угол ? = ?BSC. Боковая грань (например, треугольник SBC) — равнобедренный треугольник с боковыми сторонами SB = SC = l и основанием BC = a.

Проведем в треугольнике SBC высоту (она же медиана и биссектриса) SM к основанию BC. M — середина BC, поэтому BM = a/2.

В прямоугольном треугольнике SMB угол ?BSM = ?/2. Из определения синуса:$\sin\left(\frac{\alpha}{2}\right) = \frac{BM}{SB} = \frac{a/2}{l} = \frac{a}{2l}$

Подставим найденное ранее выражение для l:$\sin\left(\frac{\alpha}{2}\right) = \frac{a}{2\sqrt{H^2 + a^2/3}}$

Тогда искомый угол ?:$\alpha = 2\arcsin\left(\frac{a}{2\sqrt{H^2 + a^2/3}}\right)$

Ответ: $\alpha = 2\arcsin\left(\frac{a}{2\sqrt{H^2 + a^2/3}}\right)$

в) угол между боковым ребром и плоскостью основания пирамиды

Угол между боковым ребром (например, SA) и плоскостью основания ABC — это угол между ребром SA и его проекцией на плоскость основания, которой является отрезок OA. Обозначим этот угол ? = ?SAO.

Рассмотрим прямоугольный треугольник SOA.$\tan(\beta) = \frac{SO}{OA} = \frac{H}{R} = \frac{H}{a/\sqrt{3}} = \frac{H\sqrt{3}}{a}$

Отсюда угол ?:$\beta = \arctan\left(\frac{H\sqrt{3}}{a}\right)$

Ответ: $\beta = \arctan\left(\frac{H\sqrt{3}}{a}\right)$

г) угол между боковой гранью и основанием пирамиды

Угол между боковой гранью (например, SBC) и основанием ABC — это линейный угол двугранного угла при ребре BC.

Проведем апофему SM (M — середина BC). Так как SBC — равнобедренный треугольник, SM ? BC. В основании AM — медиана и высота, поэтому AM ? BC. Следовательно, искомый угол ? — это угол ?SMA. Так как точка O лежит на AM, это угол ?SMO.

Рассмотрим прямоугольный треугольник SOM.$\tan(\gamma) = \frac{SO}{OM} = \frac{H}{r} = \frac{H}{a/(2\sqrt{3})} = \frac{2H\sqrt{3}}{a}$

Отсюда угол ?:$\gamma = \arctan\left(\frac{2H\sqrt{3}}{a}\right)$

Ответ: $\gamma = \arctan\left(\frac{2H\sqrt{3}}{a}\right)$

д) двугранный угол при боковом ребре пирамиды

Двугранный угол при боковом ребре (например, SA) — это угол ? между плоскостями боковых граней SAB и SAC.

Для нахождения этого угла построим его линейный угол. Проведем в грани SAB перпендикуляр BK к ребру SA. Так как боковые грани SAB и SAC равны, то перпендикуляр из точки C к ребру SA также придет в точку K, то есть CK ? SA.

Тогда искомый угол ? = ?BKC. Треугольник BKC — равнобедренный с основанием BC = a и равными сторонами BK = CK.

По теореме косинусов для треугольника BKC:$BC^2 = BK^2 + CK^2 - 2 \cdot BK \cdot CK \cdot \cos(\delta) \implies a^2 = 2BK^2(1 - \cos\delta)$$\cos(\delta) = 1 - \frac{a^2}{2BK^2}$

Найдем длину BK. Площадь треугольника SAB можно выразить двумя способами:$S_{\triangle SAB} = \frac{1}{2} AB \cdot SM = \frac{1}{2} SA \cdot BK \implies a \cdot SM = l \cdot BK \implies BK = \frac{a \cdot SM}{l}$

Найдем квадраты длин SM и l.Из прямоугольного треугольника SOM: $SM^2 = SO^2 + OM^2 = H^2 + r^2 = H^2 + \left(\frac{a}{2\sqrt{3}}\right)^2 = H^2 + \frac{a^2}{12}$.Длина бокового ребра: $l^2 = H^2 + \frac{a^2}{3}$.

Теперь найдем $BK^2$:$BK^2 = \frac{a^2 \cdot SM^2}{l^2} = \frac{a^2 \left(H^2 + \frac{a^2}{12}\right)}{H^2 + \frac{a^2}{3}} = \frac{a^2 \frac{12H^2 + a^2}{12}}{\frac{3H^2 + a^2}{3}} = \frac{a^2 (12H^2 + a^2)}{4(3H^2 + a^2)}$

Подставим BK? в формулу для косинуса угла ?:$\cos(\delta) = 1 - \frac{a^2}{2 \cdot \frac{a^2(12H^2+a^2)}{4(3H^2+a^2)}} = 1 - \frac{2(3H^2+a^2)}{12H^2+a^2}$

$\cos(\delta) = \frac{(12H^2+a^2) - (6H^2+2a^2)}{12H^2+a^2} = \frac{6H^2 - a^2}{12H^2 + a^2}$

Отсюда угол ?:$\delta = \arccos\left(\frac{6H^2 - a^2}{12H^2 + a^2}\right)$

Ответ: $\delta = \arccos\left(\frac{6H^2 - a^2}{12H^2 + a^2}\right)$

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 254 расположенного на странице 77 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 №254 (с. 77), 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.