I have a question refarding elevation and depression of angles

Question

A man standing on the roof of a building 85.0 feet above the ground looks down to the building next door. He finds the angle of depression to the roof of the building from the roof of his building, while the angle of depression from the roof of his building to the bottom of the building next door is 42.2. How tall is the building next door?

Answer 1

construct some right triangles

angle of depression from roof to roof = A

angle of depression from roof to ground = 42.2 degrees

then base = b = 85/tan42.2 = about 93.742 feet

and a = side oppose angle A = btanA = 93.742tanA

height of smaller building = h = 85 - 93.742tanA feet