-
The angle of elevation of the top of a vertical tower situated perpendicularly on a plane is observed as 60° from a point P on the same plane. From another point Q, 10 m vertically above the point P, the angle of depression of the foot of the tower is 30°. The height of the tower is
-
- 15 m
- 30 m
- 20 m
- 25 m
Correct Option: B
AB = Tower = h metre
PQ = 10 metre
∠ APB = 60°,
∠ CQB = ∠ QBP = 30°
In ∆ PBQ,
| tan 30° = | PB |
| ⇒ | = | |||
| √3 | PB |
⇒ PB = 10 √3 metre
In ∆ APB,
| tan 60° = | PB |
| ⇒ √3 = | 10√3 |
⇒ h = √3 × 10 √3 = 30 metre
