MathDB
Configuration with median and right angles

Source: EMC 2023 Junior P3

December 18, 2023
geometry

Problem Statement

Consider an acute-angled triangle ABCABC with AB<ACAB < AC. Let MM and NN be the midpoints of segments BCBC and ABAB, respectively. The circle with diameter ABAB intersects the lines BC,AMBC, AM and ACAC at D,ED, E, and FF, respectively. Let GG be the midpoint of FCFC. Prove that the lines NF,DENF, DE and GMGM are concurrent.
Michal Pecho