In the adjoining figure, O is the centre of a circle. If ∠ OEB = 30° and C is a point on the circle then ∠ ACB =

120°
50°
30°
60°
Since, OA = OB
So, ∠ OBA = ∠ OAB = 30°
Therefore, ∠ AOB = 180° - (30° + 30°) = 120°
and from the theorem