MathDB
Equal lengths on altitude

Source: Spain MO 2023 P2

March 10, 2023
geometry

Problem Statement

Let ABCABC be an acute scalene triangle with incenter II and orthocenter HH. Let MM be the midpoint of ABAB. On the line AHAH we consider points DD and EE, such that the line MDMD is parallel to CICI and MEME is perpendicular to CICI. Prove that AE=DHAE=DH.