AB and CD are two equal chords of a circle with centre at O. If OP ⊥ AB and OQ ⊥ CD, where P and Q are points on the chords AB and CD respectively and if ∠POQ=100∘, the measure of ∠APQ is:
50∘
AB = CD, hence OP = OQ, given ∠POQ=100∘
Then ∠OPQ=40∘
∠APQ=130∘
If we interchange positions of A & B,
∠APQ=50∘.