Question

in figure 4.64 angle A b equals to 45 degree find angle ACB.

Answer 1

in the given figure

A°= 45°

To find : ACB°

ANS:

If A°=45°

then B°=45°

( OA=OB are radius of circle hence ∆OAB is isoceles ∆)

Then AOB°=180-(45+45)

=180-90

=90°

Now then ACB°=1/2AOB° (Angle subtended by chord on circumference is half of angle subtended by chord at centre)

Thus; ACB°=1/2×90°

=45°

ANS: 45°