Cосновая дощечка толщиной 2 см плавает в воде. Какова высота надводной части дощечки???

Ребята пожалуста помогите!!! ЗАРАНЕЕ ОГРОМНОЕ СПАСИБО!!!

в равнобедренном треугольнике АВС с основанием АС и медианой BD найдите угол АВС,если угол ABD равен  27 градусов 38"49"

                                  Переведите с английского на русский.

1)Sir Francis Drake was an English pirate and explorer. He set off from Plymouth for Egypt in 1577. But his ships sailed south-west across the Atlantic and he reached South America. They attacked Spanish ships there and took their tresh. Captain Drake sailed round the continent of South America. He discovered some ulans to the south of the Antarctic and South America. Then he went north and was the first person from Europe to reach the west coast of North America. He met Native Americans there. Sir Francis Drake explored a new way home from North America. He was the second captain to sail around the word. He came back home in July, 1588.

2) There's a rock called Uluru in Australia which changest its colour (to blue or red) in different weather or at different times of the day. It's also the world. There are caves with Aboriginal drawings in them.

3) James Cook set off from Plymouth in August 1768 and went south. He wanted to discover a new land ther. He didn't find the Antarctic on this trip, but he discovered and mapprd some new islans. He saw kaolas and kangaroos in Austrstia. He came back hom in July, 1771.

Исходные вещества: А) N2 Б) P2O3 В) HNO3

Реагенты: 1) O2, NaOH 2) HNO3, H2O 3) AgNO3, CuO 4) O2, Ca 5) Na2CO3, Cu

Иван 3: человек и государь. Короткое эссе (не более 100 слов)