In any nonisosceles triangle ABC, the
bisectors of the exterior angles at A, B, and C meet the
opposite sides at points D, E, and F respectively. Prove that D,
E, and F are collinear.
See also: Ceva's Theorem,
Menelaus' theorem,
Blanchet
Theorem,
Gergonne Point,
Nagel Point, Pentagons &
Pentagrams.
