Предмет: Геометрия, автор: farid64

Периметр треугольника равен 48 см. Разделив каждую сторону на 4 равные части,соединим точки деления с отрезками, параллельными соответствующим сторонам треугольника. Найдите сумму длин всех отрезков

Ответы

Автор ответа: dmital

Мы получим 3 тройки по 3 параллельных отрезка. Каждая тройка образует треугольники, подобные с коэффициентом 3/4, 2/4, 1/4 исходному треугольнику. Значит, сумма тройки отрезков равна 6/4=3/2 от длины соответствующей стороны. Значит, длина всех отрезков равна 3/2 периметра, и равна 72.

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1. Read the text and answer the questions bellow.
Environmental Protection.
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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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