MathDB
Two circles

Source: Taiwan NMO 2006

March 21, 2006
geometrycircumcircleangle bisectorgeometry proposed

Problem Statement

P,QP,Q are two fixed points on a circle centered at OO, and MM is an interior point of the circle that differs from OO. M,P,Q,OM,P,Q,O are concyclic. Prove that the bisector of PMQ\angle PMQ is perpendicular to line OMOM.