In the given figure, O is the centre of the circle. A is any point on minor arc BC. Find the value of ∠BAC−∠OBC.
Here OB = OC = radius
⇒ΔOBC is isosceles
Now in ΔOBC, by angle sum property
2y+(360∘−∠z)=180∘ [∠z is the reflex ∠ of ∠t]
Reflex ∠z=2x [Angle subtended by an arc at the centre is twice the angle subtented by it at the circumference]