What is the height in feet of the tree?

Question

Mariela is standing in a building and looking out of the window at a tree. The tree is 20 feet away from Mariela. Mariela's line of sight to the top of the tree creates a 42-degree angle od elevation and her line of sight to the base of the tree creates a 31-degree angle of depression. What is the height, in feet, of the tree? 

Answer 1

Make a sketch!

From Mariela's point up the tree height is 20 tan 42° and

from her position down is 20 tan 31°.

The height of the tre is the sum of these 2 numbers.