9.2

Part of 1998 All-Russian Olympiad Regional Round

Problems(1)

<APB =<CQD, intersecting circles - All-Russian MO 1998 Regional (R4) 9.2

Source:

Two circles intersect at points

P

Q

. The straight line intersects these circles at points

A

B

C

D

, as shown in fig. . Prove that

\angle APB = \angle CQD

. https://cdn.artofproblemsolving.com/attachments/1/a/a581e11be68bbb628db5b5b8e75c7ff6e196c5.png

geometryequal anglescircles