MathDB
Rioplatense 2022 - Level 2 - Problem 3

Source:

December 6, 2022
geometry

Problem Statement

Let ABCABC be a triangle with AB<ACAB<AC. There are two points XX and YY on the angle bisector of BA^CB\widehat AC such that XX is between AA and YY and BXBX is parallel to CYCY. Let ZZ be the reflection of XX with respect to BCBC. Line YZYZ cuts line BCBC at point PP. If line BYBY cuts line CXCX at point KK, prove that KA=KPKA=KP.