Предмет: Геометрия, автор: 898880

В основі піраміди лежить рівнобедрений трикутник з
основою 12 см і кутом 60° при вершині. Усі ребра
піраміди утворюють з площиною основи кут 30°.
Знайдіть об'єм піраміди.
З малюнком!

Приложения:

orjabinina: Не обратила внимания на буквы на Вашем чертеже.

aarr04594: 1) Оскільки кут при вершині рівнобедренного трикутника 60°, то трикутник рівносторонній. S=(12²|/3)4=36|/3(cм²). 2) Оскільки усі ребра нахилені під одним кутом, то т. О- центр описаного кола з радіусом R=AO=(12|/3)/3=4|/3( см). 3)Н=SO=AO×tg30°=4 см. 4)V=1/3×36|/3×4=48|/3(cм³).

orjabinina: Добрый день ,aarr04594. Если считаете что мое решение не соответствует правилам данного сайта , то ставьте нарушение.Кстати , эта задача была дана 3 недели назад.....Трудно ее было найти?

aarr04594: Навіщо ставити порушення, якщо правильно. Додати інший спосіб - право кожного.

Ответы

Автор ответа: orjabinina

0

В основе пирамиды лежит равнобедренный треугольник из основанием 12 см и углом 60° при вершине.

Все ребра пирамиды образуют с плоскостью основания угол 30°. Найдите объем пирамиды.

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