Question

A spherical balloon of radius r subtends an angle θ at the eve of an observer.If the angle of elevation of its centre is φ find the height of the centre of the balloon

Answer 1

In Fig. 11.49, O is the centre of balloon, where radius OP=r and ∠PAQ=θ. Also, ∠OAB=φ

Let the height of the centre of the balloon be h. Thus OB=H.