Номер 216, страница 62 - 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 2. Перпендикулярность прямых и плоскостей. Параграф 3. Двугранный угол. Перпендикулярность плоскостей, дополнительные задачи - номер 216, страница 62.

App\Models\Task {#1030 // resources/views/models/task/default.blade.php
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                        1 => App\Models\Term {#1054
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                          #attributes: array:12 [
                            "id" => 6905
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Киселёва"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Людмила"
                            "field_patronymic" => "Сергеевна"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 6905
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
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                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Людмила"
                            "field_patronymic" => "Сергеевна"
                            "field_surname_rp" => null
                          ]
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                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1063
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1064
                      #items: array:1 [
                        0 => App\Models\Term {#1065
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
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                          +exists: true
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                          #escapeWhenCastingToString: false
                          #attributes: array:10 [
                            "id" => 6671
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Учебник"
                            "field_book_type_foreign" => null
                            "field_cases" => array:6 [ …6]
                            "field_plural_form" => null
                            "field_short_name" => null
                            "field_short_name_foreign" => null
                            "field_translit" => "uchebnik"
                          ]
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                            "id" => 6671
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Учебник"
                            "field_book_type_foreign" => null
                            "field_cases" => array:6 [ …6]
                            "field_plural_form" => null
                            "field_short_name" => null
                            "field_short_name_foreign" => null
                            "field_translit" => "uchebnik"
                          ]
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                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
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                          #relations: []
                          #touches: []
                          +timestamps: true
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                          #hidden: []
                          #visible: []
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                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1066
                      #items: array:1 [
                        0 => App\Models\Term {#1067
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
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                          +exists: true
                          +wasRecentlyCreated: false
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                          #attributes: array:6 [
                            "id" => 9
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Россия"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "rossiya"
                          ]
                          #original: array:6 [
                            "id" => 9
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Россия"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "rossiya"
                          ]
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                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
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                          #relations: []
                          #touches: []
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                          #visible: []
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                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1068
                      #items: array:1 [
                        0 => App\Models\Term {#1069
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 15
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Москва"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "moskva"
                          ]
                          #original: array:6 [
                            "id" => 15
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                             …3
                          ]
                          #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: []
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #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" => 744374
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Перпендикулярность прямых и плоскостей"
            "field_branch_order" => "2"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1050}
            "field_page_start" => "36"
            "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: []
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          #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" => 744374
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Перпендикулярность прямых и плоскостей"
            "field_branch_order" => "2"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1130
              #items: array:1 [
                0 => App\Models\Term {#1047}
              ]
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "36"
            "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" => 744374
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Перпендикулярность прямых и плоскостей"
            "field_branch_order" => "2"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1130}
            "field_page_start" => "36"
            "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
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                    "id" => 2315
                    "created_at" => "2026-04-10 13:58:26"
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                    "title" => "Условие"
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            "text" => "<p> <b>216.</b> Точки А и В лежат на ребре данного двугранного угла, равного 120°. Отрезки АС и BD проведены в разных гранях и перпендикулярны к ребру двугранного угла. Найдите отрезок CD, если <span class="long"> AB = AC = BD = a.</span> </p>"
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            "edition" => Illuminate\Database\Eloquent\Collection {#1101}
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              "type" => "task"
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        1 => App\Models\Element {#1100
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        2 => App\Models\Element {#1103
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        3 => App\Models\Element {#1098
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          #table: "elements"
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            "text" => "<p>Для решения задачи воспользуемся векторным методом. Пусть ребро двугранного угла, на котором лежат точки A и B, является прямой $l$.</p><p><strong>1. Введение векторов и их свойств</strong></p><p>Введем векторы, соответствующие отрезкам из условия задачи: $\vec{AB}$, $\vec{AC}$ и $\vec{BD}$. По условию, отрезки $AC$ и $BD$ перпендикулярны ребру двугранного угла. Это означает, что векторы $\vec{AC}$ и $\vec{BD}$ перпендикулярны вектору $\vec{AB}$, который направлен вдоль ребра $l$. В виде скалярного произведения это записывается как: $\vec{AC} \cdot \vec{AB} = 0$ $\vec{BD} \cdot \vec{AB} = 0$ Также из условия известны длины отрезков, которые равны модулям соответствующих векторов: $|\vec{AB}| = AB = a$ $|\vec{AC}| = AC = a$ $|\vec{BD}| = BD = a$</p><p><strong>2. Представление вектора $\vec{CD}$</strong></p><p>Чтобы найти длину отрезка $CD$, найдем сначала вектор $\vec{CD}$. Его можно представить в виде суммы векторов, образующих ломаную линию от точки C до точки D: $\vec{CD} = \vec{CA} + \vec{AB} + \vec{BD}$ Важно отметить, что $\vec{CA} = -\vec{AC}$.</p><p><strong>3. Нахождение квадрата длины отрезка $CD$</strong></p><p>Квадрат длины отрезка $CD$ равен скалярному квадрату вектора $\vec{CD}$: $CD^2 = |\vec{CD}|^2 = \vec{CD} \cdot \vec{CD} = (\vec{CA} + \vec{AB} + \vec{BD}) \cdot (\vec{CA} + \vec{AB} + \vec{BD})$ Раскроем скобки, используя свойства скалярного произведения: $CD^2 = \vec{CA}^2 + \vec{AB}^2 + \vec{BD}^2 + 2(\vec{CA} \cdot \vec{AB}) + 2(\vec{AB} \cdot \vec{BD}) + 2(\vec{CA} \cdot \vec{BD})$</p><p><strong>4. Вычисление скалярных произведений</strong></p><p>Теперь вычислим каждое слагаемое в полученном выражении. Скалярные квадраты векторов равны квадратам их длин: $\vec{CA}^2 = |\vec{AC}|^2 = a^2$; $\vec{AB}^2 = |\vec{AB}|^2 = a^2$; $\vec{BD}^2 = |\vec{BD}|^2 = a^2$. Скалярные произведения перпендикулярных векторов равны нулю: $2(\vec{CA} \cdot \vec{AB}) = 0$ (так как $AC \perp AB$) и $2(\vec{AB} \cdot \vec{BD}) = 0$ (так как $BD \perp AB$). Остается найти значение $2(\vec{CA} \cdot \vec{BD})$. $2(\vec{CA} \cdot \vec{BD}) = 2(-\vec{AC} \cdot \vec{BD})$. Скалярное произведение $\vec{AC} \cdot \vec{BD}$ по определению равно $|\vec{AC}| \cdot |\vec{BD}| \cdot \cos\varphi$, где $\varphi$ — это угол между векторами $\vec{AC}$ и $\vec{BD}$. Отрезки $AC$ и $BD$ лежат в разных гранях и перпендикулярны ребру. Следовательно, угол между их направлениями (если совместить их начала) равен линейному углу двугранного угла, то есть $\varphi = 120^\circ$. $\vec{AC} \cdot \vec{BD} = a \cdot a \cdot \cos(120^\circ) = a^2 \cdot \left(-\frac{1}{2}\right) = -\frac{a^2}{2}$. Подставляем это значение обратно: $2(\vec{CA} \cdot \vec{BD}) = 2\left(-\left(-\frac{a^2}{2}\right)\right) = 2\left(\frac{a^2}{2}\right) = a^2$.</p><p><strong>5. Итоговый расчет</strong></p><p>Соберем все вычисленные значения в единую формулу для $CD^2$: $CD^2 = a^2 + a^2 + a^2 + 0 + 0 + a^2$ $CD^2 = 4a^2$ Теперь найдем длину отрезка $CD$, извлекая квадратный корень: $CD = \sqrt{4a^2} = 2a$</p><p>Ответ: $2a$.</p>"
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            "text" => "<p>Для решения задачи воспользуемся векторным методом. Пусть ребро двугранного угла, на котором лежат точки A и B, является прямой $l$.</p><p><strong>1. Введение векторов и их свойств</strong></p><p>Введем векторы, соответствующие отрезкам из условия задачи: $\vec{AB}$, $\vec{AC}$ и $\vec{BD}$. По условию, отрезки $AC$ и $BD$ перпендикулярны ребру двугранного угла. Это означает, что векторы $\vec{AC}$ и $\vec{BD}$ перпендикулярны вектору $\vec{AB}$, который направлен вдоль ребра $l$. В виде скалярного произведения это записывается как: $\vec{AC} \cdot \vec{AB} = 0$ $\vec{BD} \cdot \vec{AB} = 0$ Также из условия известны длины отрезков, которые равны модулям соответствующих векторов: $|\vec{AB}| = AB = a$ $|\vec{AC}| = AC = a$ $|\vec{BD}| = BD = a$</p><p><strong>2. Представление вектора $\vec{CD}$</strong></p><p>Чтобы найти длину отрезка $CD$, найдем сначала вектор $\vec{CD}$. Его можно представить в виде суммы векторов, образующих ломаную линию от точки C до точки D: $\vec{CD} = \vec{CA} + \vec{AB} + \vec{BD}$ Важно отметить, что $\vec{CA} = -\vec{AC}$.</p><p><strong>3. Нахождение квадрата длины отрезка $CD$</strong></p><p>Квадрат длины отрезка $CD$ равен скалярному квадрату вектора $\vec{CD}$: $CD^2 = |\vec{CD}|^2 = \vec{CD} \cdot \vec{CD} = (\vec{CA} + \vec{AB} + \vec{BD}) \cdot (\vec{CA} + \vec{AB} + \vec{BD})$ Раскроем скобки, используя свойства скалярного произведения: $CD^2 = \vec{CA}^2 + \vec{AB}^2 + \vec{BD}^2 + 2(\vec{CA} \cdot \vec{AB}) + 2(\vec{AB} \cdot \vec{BD}) + 2(\vec{CA} \cdot \vec{BD})$</p><p><strong>4. Вычисление скалярных произведений</strong></p><p>Теперь вычислим каждое слагаемое в полученном выражении. Скалярные квадраты векторов равны квадратам их длин: $\vec{CA}^2 = |\vec{AC}|^2 = a^2$; $\vec{AB}^2 = |\vec{AB}|^2 = a^2$; $\vec{BD}^2 = |\vec{BD}|^2 = a^2$. Скалярные произведения перпендикулярных векторов равны нулю: $2(\vec{CA} \cdot \vec{AB}) = 0$ (так как $AC \perp AB$) и $2(\vec{AB} \cdot \vec{BD}) = 0$ (так как $BD \perp AB$). Остается найти значение $2(\vec{CA} \cdot \vec{BD})$. $2(\vec{CA} \cdot \vec{BD}) = 2(-\vec{AC} \cdot \vec{BD})$. Скалярное произведение $\vec{AC} \cdot \vec{BD}$ по определению равно $|\vec{AC}| \cdot |\vec{BD}| \cdot \cos\varphi$, где $\varphi$ — это угол между векторами $\vec{AC}$ и $\vec{BD}$. Отрезки $AC$ и $BD$ лежат в разных гранях и перпендикулярны ребру. Следовательно, угол между их направлениями (если совместить их начала) равен линейному углу двугранного угла, то есть $\varphi = 120^\circ$. $\vec{AC} \cdot \vec{BD} = a \cdot a \cdot \cos(120^\circ) = a^2 \cdot \left(-\frac{1}{2}\right) = -\frac{a^2}{2}$. Подставляем это значение обратно: $2(\vec{CA} \cdot \vec{BD}) = 2\left(-\left(-\frac{a^2}{2}\right)\right) = 2\left(\frac{a^2}{2}\right) = a^2$.</p><p><strong>5. Итоговый расчет</strong></p><p>Соберем все вычисленные значения в единую формулу для $CD^2$: $CD^2 = a^2 + a^2 + a^2 + 0 + 0 + a^2$ $CD^2 = 4a^2$ Теперь найдем длину отрезка $CD$, извлекая квадратный корень: $CD = \sqrt{4a^2} = 2a$</p><p>Ответ: $2a$.</p>"
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№216 (с. 62)
Условие. №216 (с. 62)
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 62, номер 216, Условие

216. Точки А и В лежат на ребре данного двугранного угла, равного 120°. Отрезки АС и BD проведены в разных гранях и перпендикулярны к ребру двугранного угла. Найдите отрезок CD, если AB = AC = BD = a.

Решение 2. №216 (с. 62)
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 62, номер 216, Решение 2
Решение 3. №216 (с. 62)
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 62, номер 216, Решение 3
Решение 5. №216 (с. 62)
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 62, номер 216, Решение 5
Решение 6. №216 (с. 62)

Для решения задачи воспользуемся векторным методом. Пусть ребро двугранного угла, на котором лежат точки A и B, является прямой $l$.

1. Введение векторов и их свойств

Введем векторы, соответствующие отрезкам из условия задачи: $\vec{AB}$, $\vec{AC}$ и $\vec{BD}$. По условию, отрезки $AC$ и $BD$ перпендикулярны ребру двугранного угла. Это означает, что векторы $\vec{AC}$ и $\vec{BD}$ перпендикулярны вектору $\vec{AB}$, который направлен вдоль ребра $l$. В виде скалярного произведения это записывается как: $\vec{AC} \cdot \vec{AB} = 0$ $\vec{BD} \cdot \vec{AB} = 0$ Также из условия известны длины отрезков, которые равны модулям соответствующих векторов: $|\vec{AB}| = AB = a$ $|\vec{AC}| = AC = a$ $|\vec{BD}| = BD = a$

2. Представление вектора $\vec{CD}$

Чтобы найти длину отрезка $CD$, найдем сначала вектор $\vec{CD}$. Его можно представить в виде суммы векторов, образующих ломаную линию от точки C до точки D: $\vec{CD} = \vec{CA} + \vec{AB} + \vec{BD}$ Важно отметить, что $\vec{CA} = -\vec{AC}$.

3. Нахождение квадрата длины отрезка $CD$

Квадрат длины отрезка $CD$ равен скалярному квадрату вектора $\vec{CD}$: $CD^2 = |\vec{CD}|^2 = \vec{CD} \cdot \vec{CD} = (\vec{CA} + \vec{AB} + \vec{BD}) \cdot (\vec{CA} + \vec{AB} + \vec{BD})$ Раскроем скобки, используя свойства скалярного произведения: $CD^2 = \vec{CA}^2 + \vec{AB}^2 + \vec{BD}^2 + 2(\vec{CA} \cdot \vec{AB}) + 2(\vec{AB} \cdot \vec{BD}) + 2(\vec{CA} \cdot \vec{BD})$

4. Вычисление скалярных произведений

Теперь вычислим каждое слагаемое в полученном выражении. Скалярные квадраты векторов равны квадратам их длин: $\vec{CA}^2 = |\vec{AC}|^2 = a^2$; $\vec{AB}^2 = |\vec{AB}|^2 = a^2$; $\vec{BD}^2 = |\vec{BD}|^2 = a^2$. Скалярные произведения перпендикулярных векторов равны нулю: $2(\vec{CA} \cdot \vec{AB}) = 0$ (так как $AC \perp AB$) и $2(\vec{AB} \cdot \vec{BD}) = 0$ (так как $BD \perp AB$). Остается найти значение $2(\vec{CA} \cdot \vec{BD})$. $2(\vec{CA} \cdot \vec{BD}) = 2(-\vec{AC} \cdot \vec{BD})$. Скалярное произведение $\vec{AC} \cdot \vec{BD}$ по определению равно $|\vec{AC}| \cdot |\vec{BD}| \cdot \cos\varphi$, где $\varphi$ — это угол между векторами $\vec{AC}$ и $\vec{BD}$. Отрезки $AC$ и $BD$ лежат в разных гранях и перпендикулярны ребру. Следовательно, угол между их направлениями (если совместить их начала) равен линейному углу двугранного угла, то есть $\varphi = 120^\circ$. $\vec{AC} \cdot \vec{BD} = a \cdot a \cdot \cos(120^\circ) = a^2 \cdot \left(-\frac{1}{2}\right) = -\frac{a^2}{2}$. Подставляем это значение обратно: $2(\vec{CA} \cdot \vec{BD}) = 2\left(-\left(-\frac{a^2}{2}\right)\right) = 2\left(\frac{a^2}{2}\right) = a^2$.

5. Итоговый расчет

Соберем все вычисленные значения в единую формулу для $CD^2$: $CD^2 = a^2 + a^2 + a^2 + 0 + 0 + a^2$ $CD^2 = 4a^2$ Теперь найдем длину отрезка $CD$, извлекая квадратный корень: $CD = \sqrt{4a^2} = 2a$

Ответ: $2a$.

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