Предмет: Геометрия, автор: KittyAlisa

В равнобедренном треугольнике ABC (AB=BC) точка C1 —середина стороны AB, точка D — середина CC1. Точка F на стороне BC такова, что BF : FC = 3 : 1. Докажите, что AD = C1F.

Ответы

Автор ответа: abdamina1974

Ответ:

Дано: ΔАВС = равнобедренный;

АВ = ВС;

С₁ - середина АВ; D - середина CC₁;

F ∈ BC; BF : FC=3 : 1.

Доказать: AD = C₁F.

Доказательство:

Проведем С₁К || AC; FD ∩ AB = M.

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