Предмет: Геометрия, автор: Ксень2

Найдите длину окружности, вписанной в правильный треугольник, если радиус описанной около этого треугольника окружности равен 8 см.

Ответы

Автор ответа: dmital

Радиус вписанной окружности равен 1/3 высоты, а радиус описанной равен 2/3 высоты (нетрудно убедиться, построив рисунок). Тогда радиус вписанной окружности равен 4, а длина равна 8pi.

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1. True / false task:
By-products of the factories pollute the air, water and fields.
True
False
The text doesn't say.

The mixture of car gases is carried for hundreds of miles by the wind and finally disappears.
True
False
The text doesn't say.

Dumping wastes may also get into the soil.
True
False
The text doesn't say.

Recycling waste and rubbish receives ever-greater care in least developing countries.
True
False
The text doesn't say.

As a result of the pollution, more than 10 per cent of the world's purest water has been ruined.
True
False
The text doesn't say.

Active measures should be taken to create an international system of ecological security.
True
False
The text doesn't say.

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