XR is a tangent to the circle. O is the centre of the circle. If ∠XRP = 120º, then what is the value (in degrees) of ∠QOR?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 60
∠XRO = 90°
⇒ ∠ORP = ∠XRP – ∠XRO
= 120 – 90 = 30°
In triangle ORP
⇒ OR = OP = radius of the circle
⇒ ∠OPR = ∠ORP = 30°
⇒ ∠QOR = ∠OPR + ∠ORP (Exterior angle = Sum of other two interior angles)
= 30 + 30 = 60°