SSC CPO 9 Dec 2019 Shift 1 Paper

A clock tower stands at the crossing of two roads which point in the north-south and the east-west directions. P, Q, R and S are points on the road due north, east, south and west respectively, where the angles of elevation of the top of the tower are respectively, α, β, γ and δ. Then (PQ/RS)² is equal to: