Two circles intersect at two points B and C. Through B, two line segments ABD and PBQ are drawn to intersect the circles at A, D and P, Q respectively (see figure). Prove that .
We need to prove that
(Angles in the same segment) (1)
(Angles in the same segment) (2)
We also have (Vertically Opposite Angles) (3)
From (1), (2) and (3), we get