MathDB
Prove that the Points Lie on a Circle

Source: ToT - 2001 Spring Senior O-Level #3

August 17, 2011
geometryperpendicular bisectorgeometry unsolved

Problem Statement

Points XX and YY are chosen on the sides ABAB and BCBC of the triangle ABC\triangle ABC. The segments AYAY and CXCX intersect at the point ZZ. Given that AY=YCAY = YC and AB=ZCAB = ZC, prove that the points BB, XX, ZZ, and YY lie on the same circle.