(***************************************************************************)
(* Formalization of the Chou, Gao and Zhang's decision procedure.          *)
(* Julien Narboux (Julien@narboux.fr)                                      *)
(* LIX/INRIA FUTURS 2004-2006                                              *)
(* University of Strasbourg 2008                                           *)
(***************************************************************************)
Require Export area_method.
(* A small lemma to check that centroid is really at the intersection of medians. *)

Lemma euler_line : forall A B C H O G,
is_circumcenter O A B C ->
is_orthocenter H A B C ->
is_centroid G A B C ->
Col O G H.