Question

In the figure O is the centre of the circle .angle BAO=20°angle BCO=10°. what is the measure of angle ABC?.what is the measure of angle AOC?.what is the measure of angle ADC?.find the angles of triangle AOC?. If the diameter of the circle is 10cm then,find the length of the chord AB?.​

Answer 1

Step-by-step explanation:

In △ABO, AO=BO⇒∠BAO=∠ABO=30o

In △CBO, CO=BO,⇒∠BCO=∠CBO=40o

⇒∠ABC=∠ABO+∠CBO=30+40=70o

Angle subtended at the center is twice the angle subtended anywhere on the arc, so,

∠AOC=2×∠ABC=140o