PA and PB are two tangents from a point P outside a circle with center O. If A and B are points on the circle such that ∠APB = 80º, then ∠OAB is equal to:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 40°
As we know, PA = PB [length of tangents from a point P is equal]
So, triangle PAB is isosceles.
⇒ ∠PAB = ∠PBA = (180º - 80º)/2 = 50º
∠OAP = 90º [radius is perpendicular to the tangent]
⇒ ∠OAB = 90º - ∠PAB = 90º - 50º = 40º