UPTET Feb 2014, q124
0. In the figure given below, if ∠OAB = 40°,
then ∠ACB is equal to
- Option : A
- Explanation : In ΔOAB, OA = OB (Radius of the circle)
∴ ∠OBA = ∠OAB = 40°
⇒ ∠AOB = 180° - ∠OAB - ∠OBA = l80° - 80°
i.e. ∠AOB =100°
⇒ ∠ACB = 1/2∠AOB [Degree measure theorem]
∠ACB=50°
