Question

Make a circle, a chord AB. Now join A to O(center of the circle), so angle aob=40°.then find angle OAB...

Answer 1

We know that angle AOB is 40

AO and OB are radii

So angle opposite to the radii are equal

So Angle OAB = OBA

BY ANGLE SUM PROPERTY,

ANGLE AOB + ANGLE OAB + ANGLE OBA = 180

40 + 2 OAB = 180

2 OAB = 140

ANGLE OAB = 70°