MathDB
Midpoint of the internal bisector

Source: ITAMO 2019 #5

May 3, 2019
geometryITAMO 2019

Problem Statement

Let ABCABC be an acute angled triangle.. Let DD be the foot of the internal angle bisector of BAC\angle BAC and let MM be the midpoint of AD.AD. Let XX be a point on segment BMBM such that MXA=DAC.\angle MXA=\angle DAC. Prove that AXAX is perpendicular to XC.XC.