The length of the shadow of a vertical tower on level ground increased by 10 m when the altitude of the sum changes from 45° to 30°. The height of the tower is:

Solution (By Examveda Team)

$$\eqalign{ & AB = 10 \cr & \left( {\sqrt 3 - 1} \right) \to 10 \cr & 1 \to \frac{{10}}{{\sqrt 3 - 1}} \cr & = \frac{{10\left( {\sqrt 3 + 1} \right)}}{2} \cr & = 5\left( {\sqrt 3 + 1} \right) \cr} $$