Предмет: Математика, автор: valya1473

Найдите площадь трапеции, основания которой равны 8см и 14 см, а диагональ длиной 8√3 см образует с большим основанием угол 30°

Ответы

Автор ответа: Andryha2210

Ответ:

Сторона, лежащая против угла 30 градусов равна половине гипотенузы то есть высота трапеции равна 4 корней из 3средняя линия =(a+b)/2=(8+14)/2=11s=(a+b)*h/2=((8+14)*4 корней из 3)/2=44 корней из 3

valya1473: а почему треугольник прямоугольный?

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Предмет: Английский язык, автор: hdkslxkndjzkxjjdjsj

Complete the summary of the text in the previous exercise with the words from the box. There are more words than you need.

( nourishing, unemployment, originate, desire, attractive, hoodia, overcome, ideal, material, obesity, cactus, traditional)

The San are a tribe of hunter-gathereres in the Kalahari Desert whose (1) ..... lifestyle is changing fast. They now suffer from "modern" problems such as poverty and (2) ..... . Since ancient times, they have used a cactus-like plant, hoodia, to help (3) ..... hunger when food was scarce. In the West, where (4) ..... is becoming a major health issue, hoodia is seen as a solution as it appears to control the (5) ..... to eat.

A. The San live in Africa, in the Kalahari Desert. Life there is hard, and nature can be harsh. There are somewhere between 45,000 and 100,000 of them living in Zambia and Zimbabwe. They're the San, a tribe of hunter- gatherers, who used to travel in search of food for their families instead of growing it or keeping animals. They have a culture that is 20,000 years old, but their old way of life is disappearing fast and has nearly gone hrever. They don't have many material possessions like cars or computers, things that people in the developed world can't do without. But they do have one thing that certain people in the developed world are very, very interested in and want to have, and that may make them some money. It's called hoodia.
B. Many countries have basic, common crops that people plant for food, such as rice or potatoes. Potatoes are grown in many European countries as well as South America, and rice is a staple food in Asia. Some plants are grown as medicine. A few examples are garlic, which is said to help with colds or high blood pressure, ginger to help with headaches or toothache, or the magnolia tree which is used in Chinese traditional medicine to treat some forms of cancer and heart disease. Hoodia, a cactus-like plant, only grows in the area where the San live. They have known about it for centuries, but they don't use it for food. They use it to fight hunger.
C. In the old days when the San had to travel in search of food, they and their children sometimes had to go without tood for several days. This was even longer in times of famine or when the rains failed. They ate the hoodia plant when they were starving to help them survive until they found food. However, it didn't give them energy like normal food would. Instead, the chemicals in the hoodia plant killed the feeling of hunger and stopped them wanting food.

D. Scientists have now discovered that the plant contains a substance which they have called P57. This chemical makes the brain believe that the stomach is full and that the body doesn't need food.
E. Obesity in the developed world is a huge and growing problem, not only among adults, but increasingly among children. It has been estimated that up to 50% of people in the developed world are overweight and 20% of these are obese. One cause of obesity is eating too much, to often, and another is eating the wrong kind of food. Today, we have less time to cook, and we have more money, so the easiest thing to do is to buy ready-made meals high in fat, salt, and sugar. Too much of these makes people unhealthy and fat. They need to lose weight, and that's where hoodia comes in.
F. It seems to be the perfect solution. People in the west want to lose weight and hoodia is ideal. Western companies pay for the right to use the secrets of the hoodia plant; by selling these rights to the West, the San make money and can help themselves. Obese people lose weight and the San people make a profit, so everyone is happy.