Problem

Source: Balkan MO Shortlist 2008 G3 BMO

Tags: geometry, perimeter, angles, area of a triangle, bisector, orthocenter, IMO Shortlist



We draw two lines $(\ell_1) , (\ell_2)$ through the orthocenter $H$ of the triangle $ABC$ such that each one is dividing the triangle into two figures of equal area and equal perimeters. Find the angles of the triangle.