1.

In Fig. if PR is tangent to the circle at P and Q is the centre of the circle, then ∠POQ =A. 110° B. 100° C. 120° D. 90°

Answer»

Answer is C. 120°

Given: 

∠RPQ = 60° 

Property 1: The tangent at a point on a circle is at right angles to the radius obtained by joining center and the point of tangency. 

Property 2: Sum of all angles of a triangle = 180°. 

By property 1, ∆OPR is right-angled at ∠OPR (i.e., ∠OPR = 90°). 

OP = OQ [∵ radius of circle] 

∴ ∠OPQ = ∠OQP = 30° 

Now by property 2, 

∠OPQ + ∠OQP + ∠POQ = 180° 

⇒ 30° + 30° + ∠POQ = 180° 

⇒ 60° + ∠POQ = 180° 

⇒ ∠POQ = 180° - 60° 

⇒ ∠POQ = 120° 

Hence, ∠POQ = 120°



Discussion

No Comment Found

Related InterviewSolutions