proposition: Lemma RhombusExABC2: forall A B C, ~Col A B C -> Cong A B B C -> exists D, Rhombus A B C D.
proof: Proof. intros. assert(exists D, Plg A B C D). apply PlgExABC2;trivial. destruct H1 as [D H2]. exists D. unfold Rhombus in *. tauto. Qed.
imports: GeoCoq.Tarski_dev.Annexes.perp_bisect