Require Export GeoCoq.Elements.OriginalProofs.lemma_congruencesymmetric.
Section Euclid.
Context `{Ax:euclidean_neutral}.

(* Specifications: *)
Lemma lemma_congruencetransitive :
forall A B C D E F,
Cong A B C D -> Cong C D E F ->
Cong A B E F.