Require Export GeoCoq.Elements.OriginalProofs.lemma_congruenceflip.
Require Export GeoCoq.Elements.OriginalProofs.lemma_lessthancongruence.
Section Euclid.
Context `{Ax:euclidean_neutral_ruler_compass}.

(* Specifications: *)
Lemma lemma_TGsymmetric :
forall A B C a b c,
TG A a B b C c ->
TG B b A a C c.