(* Exercise done by David Braun under the supervision of Nicolas Magaud, cleaned up by Julien Narboux. *)
Require Export GeoCoq.Tarski_dev.Annexes.midpoint_theorems.
Section T_42.
Context `{TE:Tarski_euclidean}.

Lemma midpoint_thales : forall O A B C : Tpoint,
~ Col A B C ->
Midpoint O A B ->
Cong O A O C ->
Per A C B.