A vertical tower subtends the same angle at each of two places and

MATHEMATICS · Single correct · A Level · Mathematics · Trigonometry · Trigonometry

Problem

A vertical tower

PQ

subtends the same angle

30^\circ

at each of two places

A

and

B

60\text{ m}

apart on the ground. The line segment

AB

subtends an angle

120^\circ

at the foot of the tower. If

h

is the height of the tower, then

9h^2+h+1

is equal to (1)

3121

(2)

2136

(3)

3600

(4) None of these