Question

In Fig. 10.13, if ∠OAB = 40°, then ∠ACB is equal to *

2 points



45

50

65

70

Please give correct answer this question with full explanation
I will mark him brainliest ​

Answer 1

Answer:

50°

Step-by-step explanation:

□In triangle OAB,OA=OB

□/_OAB=/_OBA=/_OAB=40°

[angles opposite to equal sides are equal] Also, ∠AOB + ∠OBA + ∠BAO = 180°

[by angle sum property of a triangle]

∠AOB + 40° + 40° = 180°

⇒ ∠AOB = 180° – 80° = 100°

We know that, in a circle, the angle subtended by an arc at the centre is twice the angle subtended by it at the remaining part of the circle.

∠AOB = 2 ∠ACB ⇒ 100° =2 ∠ACB

∠ACB = 100°/2 = 50