MathDB
Problem 2, Olympic Revenge 2013

Source: XII Olympic Revenge - 2013

January 26, 2013
geometrycircumcirclesimilar trianglesperpendicular bisector

Problem Statement

Let ABCABC to be an acute triangle. Also, let KK and LL to be the two intersections of the perpendicular from BB with respect to side ACAC with the circle of diameter ACAC, with KK closer to BB than LL. Analogously, XX and YY are the two intersections of the perpendicular from CC with respect to side ABAB with the circle of diamter ABAB, with XX closer to CC than YY. Prove that the intersection of XLXL and KYKY lies on BCBC.