Pat needs to determine the height of a tree before cutting it down to be sure that it will not fall on a nearby fence. The angle of elevation of the tree from one position on a flat path from the tree is H = 30, and from a second position L = 20 feet farther along this path it is B = 20. What is the height of the tree? The height of the tree is approximately ft. (Do not round until the final answer. Then round to the nearest tenth as needed.)