In figure given below, O is the centre of the circle, use the given information to find the value of x:

As we know that the angle subtended by a diameter at any point on the circumference of a circle is a right angle (90°).

⇒ ∠APB = 90°

According to exterior angle theorem,

Exterior angle of a triangle is equal to the sum of the two opposite interior angles.

⇒ ex. ∠A = ∠APB + ∠ABP

⇒ 130° = 90° + x

⇒ x = 130° - 90°

⇒ x = 40°.

Hence, the value of x = 40°.