MathDB
easy geometry

Source: 2007 Flanders Math Olympiad, Problem 2

April 26, 2015
geometrynational olympiadbelgium

Problem Statement

Given is a half circle with midpoint OO and diameter ABAB. Let ZZ be a random point inside the half circle, and let XX be the intersection of OZOZ and the half circle, and YY the intersection of AZAZ and the half circle.
If PP is the intersection of BYBY with the tangent line in XX to the half circle, show that PZBXPZ \perp BX.