MathDB
Nice Collinearity

Source: KöMaL A. 831

October 11, 2022
geometrykomal

Problem Statement

In triangle ABCABC let FF denote the midpoint of side BCBC. Let the circle passing through point AA and tangent to side BCBC at point FF intersect sides ABAB and ACAC at points MM and NN, respectively. Let the line segments CMCM and BNBN intersect in point XX. Let PP be the second point of intersection of the circumcircles of triangles BMXBMX and CNXCNX. Prove that points A,FA, F and PP are collinear.
Proposed by Imolay András, Budapest