MathDB
Parallelogram and equality of angles

Source: Serbian National Olympiad 2012, Problem 1

April 4, 2012
geometryparallelogramcircumcircletrigonometrygeometry proposed

Problem Statement

Let ABCDABCD be a parallelogram and PP be a point on diagonal BDBD such that PCB=ACD\angle PCB=\angle ACD. Circumcircle of triangle ABDABD intersects line ACAC at points AA and EE. Prove that AED=PEB.\angle AED=\angle PEB.