(* Gabriel Braun November 2012 *)
Require Export GeoCoq.Tarski_dev.Ch12_parallel.
Section Quadrilateral.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma plg_to_parallelogram : forall A B C D, Plg A B C D -> Parallelogram A B C D.