В равнобедренном треугольнике биссектрисы, проведённые к боковым сторонам, равны.
Доказательство: Пусть ABC - равнобедренный треугольник (AC = BC), AK и BL - его биссектрисы. Треугольники AKB и ALB равны по второму признаку равенства треугольников. У них сторона AB общая, углы LAB и KBA равны как углы при основании равнобедренного треугольника, а углы LBA и KAB равны как половины углов при основании равнобедренного треугольника. Так как треугольники равны, их стороны AK и LB - биссектрисы треугольника ABC - равны. Теорема доказана.
In modern global world more and more people study foreign languages. The question about the best way to do it has (causes) a lot of debates. Some people believe that it is impossible to speak the foreign language fluently without visiting its native country. Others find it not obligatory.
I personally think that it is not a problem to learn a foreign language in its home country. There are a great number of possibilities for it. To begin with, today every school and university give an opportunity to study a foreign language . Teachers and tutors in educational institutions do their best to help students to get knowledge. Besides, there are a lot of language courses. They give a large choice of different programs. So you can choose the most suitable one according to your level and purposes. Furthermore, nowadays there is a wonderful opportunity to study it using a computer. There is a large variety of educational programms and electronic dictionaries. Moreover, you can watch foreign films in the original.
But many people believe that the only way to have a good result at language studying is to communicate with native speakers. So they find it obligatory to study abroad. To my mind it is not a necessarily thing. It is not difficult today to communicate with foreigners. Using the Internet you can chat with people from all over the world.
To sum it up, it seems to me that communication with native speakers is very important for those who want to master the language. But I see some ways to connect with them without studying abroad.
1) 100% - 30% = 70% - свежих грибов для сушки.
2) 15 • 0,7 = 10,5 (кг) - свежих грибов для сушки.
3) 100% - 76% = 24% - сухих грибов от массы свежих грибов.
4) 10,5 • 0,24 = 2,52 (кг) - сушеных грибов.
Ответ. 2,52 кг.