MathDB
6 points on a circle

Source: Turkey National Mathematical Olympiad 2021 P3

January 6, 2022
geometry

Problem Statement

A circle Γ\Gamma is tangent to the side BCBC of a triangle ABCABC at XX and tangent to the side ACAC at YY. A point PP is taken on the side ABAB. Let XPXP and YPYP intersect Γ\Gamma at KK and LL for the second time, AKAK and BLBL intersect Γ\Gamma at RR and SS for the second time. Prove that XRXR and YSYS intersect on ABAB.