AB is a chord of a circle with centre O. C is a point on the circle in the minor sector. If ∠ABO = 50°, then what is the deree measure of ∠ACB?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 140°
OA = OB = radius of the circle
∠ABO = ∠BAO = 50°
So, ∠AOB = 180 - (50 + 50) = 80°
Let A and B meet at point D in the major sector
Now, ∠ADB = 80°/2 = 40°
ABCD is a cyclic quadrilateral
So, ∠ACB = 180° - 40° = 140°