Предмет: Геометрия, автор: OneTET

Основания трапеции равны 16 см и 41 см. Найти площадь этой трапеции, если боковые стороны равны 15 см и 20 см.

Ответы

Автор ответа: Пеппер

26

Опустим из вершин углов при основании ВС высоты ВН и СК к АД.Высоты разделили основание АД на три отрезка.Обозначим отрезок АН=хОтрезок КН = ВС=16 см , поэтому отрезокКД=41-16-х=25-хНайдем квадрат высоты ВН (СК) из прямоугольных треугольников, примыкающих к боковым сторонам, где эти стороны - гипотенузы. ВН²=АВ²-х²СК²=СД²-(25-х)²
АВ²-х²=СД²-(25-х)²225-х²=400 - (625-50х+х²)225-х² =400- 625+50х -х²50х=450
х=9
АН=9 см, ВН=12 см (египетский треугольник)

S=(16+41):2*12=342 cм²

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Paul Miller is a journalist, so you would think that he would find it pretty difficult to give up using the internet for a year. (1) …..... , that’s exactly what he decided to do. It’s not that Paul didn’t (2) …..... going online. In fact, he found he was spending a large part of his day glued to the screen. He felt that he had become too (3) …..... on it for everything. Like many of us, Paul couldn’t imagine (4) …..... the internet for a full day, not checking his emails and his Twitter account. How on earth would he cope (5) ...….. being offline for a whole year? Paul has just (6) ...….. the halfway point of his challenge – six months with no internet have passed. And so what has it been like for him? Well, Paul admits that, at first, he did find it very (7) …..... not being able to contact people online. As you'd (8) ...….. , it was the social networking sites that he missed most of all. Interestingly, Paul is now finding it easier (9) …........ than harder as the weeks without the internet go by. He finds that he has much more time to read books and meet friends face to face these days. He advises other people to (10) …..... a go at living without the internet, even if they can’t manage it for a whole year!

Вопрос 1
Paul Miller is a journalist, so you would think that he would find it pretty difficult to give up using the internet for a year. (1) …..... , that’s exactly what he decided to do.

Выберите один ответ:
a.Instead
b.Although
c.Despite
d.However

Вопрос 2
It’s not that Paul didn’t (2) …..... going online. In fact, he found he was spending a large part of his day glued to the screen.
Выберите один ответ:

a.wish
b.like
c.want
d.satisfy

Вопрос 3
He felt that he had become too (3) …..... on it for everything.

Выберите один ответ:
a.dependent
b.influenced
c.reliable
d.self-confident

Вопрос 4
Like many of us, Paul couldn’t imagine (4) …..... the internet for a full day, not checking his emails and his Twitter account.

Выберите один ответ:
а.trying out
b.giving up
c.going ahead
d.getting on

Вопрос 5
Ответ сохранен
How on earth would he cope (5) ...….. being offline for a whole year?
Выберите один ответ:
a.over
b.with
c.for
d.along

Вопрос 6
Paul has just (6) ...….. the halfway point of his challenge – six months with no internet have passed.
Выберите один ответ:
a.arrived
b.reached
c.come
d.got

Вопрос 7
Well, Paul admits that, at first, he did find it very (7) …..... not being able to contact people online.
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b.believe
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a.except
b.otherwise
c.rather
d.unless

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He advises other people to (10) …..... a go at living without the internet, even if they can’t manage it for a whole year!

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