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(* Formalization of the Chou, Gao and Zhang's decision procedure.          *)
(* Julien Narboux (Julien@narboux.fr)                                      *)
(* LIX/INRIA FUTURS 2004-2006                                              *)
(* University of Strasbourg 2008                                           *)
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(** nine point circle *)
(** another statement for nine point circle theorem *)

Lemma l6_46 : forall A B C F N K J,
is_midpoint F A B ->
on_line N C F ->
on_foot K N A C ->
on_foot J N B C ->
Py N K N * Py A C A = Py N J N * Py B C B.