Question

From a point A on the ground, the angles of elevation of the top of a 10 m tall building and a helicopter hovering at some height of the building are 30° and 60° respectively. Find the height of the helicopter above the building.

(a) 10√3 m

(b) 20(3 + √3)m

(c) 20 m

(d) 30 m

Answer 1

Correct option is (c) 20 m

Given AC = 10, ∠ABC = 30°, ∠ABD = 60°, let CD = h