Một tòa nhà có chiều cao h (m).Khi tia nắng tạo với mặt đất một góc 55 độ thì bóng của tòa nhà trên mặt đất dài 15m. Tính chiều cao h của tòa nhà?

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

The two square pyramids are similar. find the total volume of both pyramids if the ratio of their surface areas is 9/16

Over the course of the school year, you keep track of how much snow falls on a given day and whether it was a snow day. your data indicates that of twenty-one days with less than three inches of snow, five were snow days, while of the eight days with more than three inches of snow, six were snow days. if all you know about a day is that it is snowing, what is the probability that it will be a snow day?