Inside a square PQRS, ΔQRT is an equilateral triangle, if RT and QS intersect at O, then ∠QOR is equal to? |
60° 45° 75° 90° |
75° |
In ΔTQR: all angles = 60° (equilateral Δ) ∠OQR = 45° [angle by diagonal] ⇒ In ΔOQR: ∠QOR + ∠OQR + ∠QRO = 180° ∠QOR + 45° + 60° = 180° ∴ ∠QOR = 75° |