Вопрос школьника по предмету Математика
В треугольнике ABC с прямым углом A прямая, перпендикулярная стороне AC, пересекает стороны AC и BC в точке D и E соответственно. Найдите длину отрезка ED, если AB=33, BE=20, BC=60
Ответ учителя по предмету Математика
Треугольники АВС и DЕС подобны по двум углам:
углы А и СDЕ прямые, а угол С общий.
Поэтому ED/AB=EC/ВС;
ED=AB*EC/ВС=AB*(ВС-ВЕ)/(BC-BE) = 33*(60-20)/60 = 22.
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When the world was at a very primitive stage of development there were no laws to regulate life of people. If a man chose to kill his wife or if a woman succeeded in killing her husband that was their own business and no one interfered officially.
But things never stay the same. The life has changed. We live in a complicated world. Scientific and social developments increase the tempo of our daily living activities, make them more involved. Now we need rules and regulations which govern our every social move and action. We have made laws of community living.
Though laws are based on the reasonable needs at the community we often don’t notice them. If our neighbor plays loud music late at night, we probably try to discuss the matter with him rather than consulting the police, the lawyer or the courts. When we buy a TV set, or a train ticket or loan money to somebody a lawyer may tell us it represents a contract with legal obligations. But to most of us it is just a ticket that gets us on a train or a TV set to watch.
Only when a neighbor refuses to behave reasonably or when we are injured in a train accident, the money wasn’t repaid, the TV set fails to work and the owner of the shop didn’t return money or replace it, we do start thinking about the legal implications of everyday activities.
You may wish to take legal action to recover your loss. You may sue against Bert who didn’t pay his debt. Thus you become a plaintiff and Bert is a defendant. At the trial you testified under oath about the loan. Bert, in his turn, claimed that it was a gift to him, which was not to be returned. The court after the listening to the testimony of both sides and considering the law decided that it was a loan and directed that judgment be entered in favor of you against Bert.
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On the whole it seems that people all over the world are becoming more and more accustomed to using legal means to regulate their relations with each other. Multinational companies employ lawyers to ensure that their contracts are valid whenever they do business.