Question

A vertical tower stands an a horizontal plane and is surmounted by a vertical flagstaff of height h metre. At a point on the plane the  angle of elevation of the bottom of the flagstaff is α and at the top of the flagstaff is β . Prove that the height of the tower is  htanα/(tanβ - tanα)

Answer 1

Let AB be the tower of height X metre , surmounted by a vertical flagstaff AD . Let C be a point on the plane such that ∠ACB = α , ∠DCB = β and AD = h.