Question

In the given fig. O is the centre af a circle .If angle OAB =40° and C is a point on the circle,then angle ACB=

a) 40° b) 50° c) 80° d) 100°​

Answer 1

hey , where's the fig ?

anyway,

check the image out i think the fig should be...

sol.

in triangle AOB

angle OAB= angle OBC ( isosceles triangle as ao and ob are radius of a circle)

so, in triangle AOB,

40°+40°+ angle AOB= 180°( sum of angles of triangle= 180)

by solving above eq,

angle aob= 100°

1/2* angle AOB= angle AOC

(theorem)

so putting the gotten val of aob and solving the above equation, aoc= 50°

ans is opt b

hope it helps