Question

If the angles of elevation of a tower from two points distant a and b (a>b) from its foot and in the same straight line from it are 30° and 60°, then the height of the tower is

(a) $\sqrt{a+b}$

(b) $\sqrt{ab}$

(c) $\sqrt{a-b}$

(d) $\sqrt{\frac{a}{b}}$

Answer 1

Let be the height of tower

Given that: angle of elevation are and.

Distance and

Here, we have to find the height of tower.

So we use trigonometric ratios.

In a triangle,

Again in a triangle ABD,

Put

Hence the correct option is .