MathDB
Nice geometry problem

Source: IZHO2015.P2

January 13, 2015
geometrysymmetrytrigonometrygeometry proposed

Problem Statement

Inside the triangle ABC ABC a point M M is given. The line BM BM meets the side AC AC at N N . The point K K is symmetrical to M M with respect to AC AC . The line BK BK meets AC AC at P P . If AMP=CMN \angle AMP = \angle CMN , prove that ABP=CBN \angle ABP=\angle CBN .