Question

In the fig., o is the center of the circle. If angle OUT is 90 degree, find angle ACB.

Answer 1

since angle AOB=120°

angle ACB =60°

Answer 2

Answer : 60°

Step-by-step explanation :

O is center that's why OA and OB will be radius.

So, OA = OB [ Radius are always same ]

∠OAB = ∠OBA

Here, ∠OAB = 30°

So, ∠OBA = 30°

Due to angle sum property

∠OAB + ∠OAB + ∠AOB = 180°

30° + 30° + ∠AOB = 180°

∠AOB = 180° - 60° = 120

Since angle subtended by an arc with center is twice the angle subtended by arc at rest if circle.

∠AOB = 2∠ACB

120° = 2∠ACB

60° = ∠ACB