Intersections of Perpendiculars From the Altitude Foot and Base Endpoints
Channel: Saltire Software
Date: 2020-11-16

The perpendiculars dropped from the foot of the altitude from A of the triangle ABC upon the sides AB, AC meet the perpendiculars erected to BC at B, C in the points I, H respectively.  Prove that the line IH passes through the orthocenter of ABC.