MathDB

3

Part of 2014 South africa National Olympiad

Problems(1)

Angles of obtuse triangle with given lines parallel

Source: South African MO 2014 Q3

10/25/2014
In obtuse triangle ABCABC, with the obtuse angle at AA, let DD, EE, FF be the feet of the altitudes through AA, BB, CC respectively. DEDE is parallel to CFCF, and DFDF is parallel to the angle bisector of ∠BAC\angle BAC. Find the angles of the triangle.
geometryangle bisectorgeometry unsolved