If the angles of elevation of the top of a tower from two points distant a and b from the base and in the same straight line with it are complementary, then the height of the tower is

Since the angles of elevation are complementary then if one angle is θ other would be 90° - θ


Here CD is the height of tower which forms two complementary angles θ and 90° - θ from its top to the distance a meters and b meters respectively.


In Δ CAD


1


In Δ CBD





Putting value of tan θ From 1



(CD)2 = ab


CD = √ab

5