Question

In a circle with centre O and chord AB if angle OAB is 60 degree. What is the measure of angle OBA why? What is the measure of angle AOB​

Answer 1

Answer:

We know that,

angle sum property of a triangle=180degree

let the first side be OAB

Second side be OBA

and Third side be AOB

given,OAB=60

OBA=AOB[angel opp.to each other]–(1)

Therefore,OAB+OBA+AOB=180

60+(OBA+OBA)=180 –from(1)

2OBA=180-60

OBA=120/2=60.

Since OBA=AOB=60 degree.

Answer 2

Answer:

Since, AO=OB.

Therefore, angle OAB=angle OBA=60° (angle opposite to equal sides are equal)

ANGLE OAB+angleOBA+angleAOB=180° (Angle sum property)

60°+60°+AOB=180°

120°+AOB=180°

AOB=60°