Предмет: Геометрия, автор: помогите1284

Треугольник АВС-равнобедренный. AB=АС. Угол B=70°. Найдите А

Ответы

Автор ответа: mixailmark0909

Угол А=180°-2*угВ=180°-140°=40°
Ответ: 40°.

Автор ответа: faithful0fellow

Т.к. стороны АВ и АС равны углы ∠В и ∠С тоже равны по свойству р\б треугольника .
Сумма углов треугольника АВС= ∠А+∠В+∠С 180=∠А+70+70 следовательно А=40°

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