The angle of elevation of the tip of a tower from a point

• Quant Trigo

The angle of elevation of the tip of a tower from a point on the ground is 45°. Moving 21 m directly towards the base of the tower, the angle of elevation changes to 60°. What is the height of the tower, to the nearest meter?

1. 48 m
2. 49 m
3. 50 m
4. 51 m

Answer

Let height of tower = h

tan 60° = h/x

x = h/√3

tan 45° = h/(21+x)

21 + x = h

21 = h - h/√3

The correct option is C.