Question

A window in a building is at a height of 10 m from the ground. The angle of depression of a point P on the ground from the window is 30 degree. The angle of elevation of the top of the building from the point P is 60 degrees. Find the height of the building.

Answer 1

from the figure,
tan 30 = 10 / X
Therefore, X = 10/tan30

And tan60 = H/X
Therefore,
H = Xtan60
= (10/tan30)*(tan60)
= \[10*\sqrt{3}*\sqrt{3} = 10*3 = 30m \]