The figure given below, shows a circle with centre O.
Given : ∠ AOC = a and ∠ ABC = b.
(i) Find the relationship between a and b.
(ii) Find the measure fo angle OAB, if OABC is a parallelogram.
(Angle at the centre is double the angle at the circumference subtended by the same chord)
(ii) Since OABC is a parallelogram, so opposite angles are equal