Предмет: Геометрия, автор: Max111111111

. В равнобедренной трапеции один из углов равен 120˚, а меньшее основание равно 8 см, найдите периметр трапеции, если боковая сторона равна меньшему основанию.

Ответы

Автор ответа: Golikov
0

проведем высоты  из меньшего основания. угол между меньшим основанием и боковой стороны равен 120 по условию, тогда угол прилежащий к этой стороне равен 60. после проведения высот у нас образовался прямоугольный треугольник. верхний его угол равен 30 гр. тогда нижний катете равен 4 .также и с другой стороны. а нижнее основание равно 16. периметр=  16+16+8=40

Автор ответа: ПроверкаДЗ
0

Мы можем провести две высоты ВК и  СН ...т.к меньшее основание ВС=8см...следовательно КН=ВС=ВК=СD=8 см...Находим угодл АВК...Т.к. угол ВКА=90 градусам следовательно АВК равно 30 градусам. Т.к. В теругольнике 180 градусов мы можем вычислить ВАК=180-(30=90)=60 градусов...и теперь через синус мы можем найти АВ. sin угла А=корень из 3 делённое на 2. Теперь можем сделать соотношение.Получается Корень из 3 делённое на два= 8 делённое на АВ. АВ= 8*2/корень из 3=16/корень из 3. АВ=СD=16/на корень из 3. Периметр= 16+16+8+848

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Fill in the gaps (1-6) with the missing sentences (A-G). There is one extra sentence.

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