Tricky triangle problem
Source: Iran 2002
August 20, 2005
trigonometrygeometryratiogeometric transformationreflectioninvarianttrapezoid
Problem Statement
Let and be points on the side of triangle , with the point lying on the segment , such that BM \equal{} CN. Let and be points on the segments and , respectively, such that \measuredangle PMC \equal{}\measuredangle MAB and \measuredangle QNB \equal{}\measuredangle NAC. Prove that \measuredangle QBC \equal{}\measuredangle PCB.