Require Export GeoCoq.Elements.OriginalProofs.lemma_rayimpliescollinear.
Require Export GeoCoq.Elements.OriginalProofs.lemma_ray2.
Require Export GeoCoq.Elements.OriginalProofs.lemma_collinearitypreserved.
Require Export GeoCoq.Elements.OriginalProofs.lemma_raystrict.
Section Euclid.
Context `{Ax:euclidean_neutral_ruler_compass}.

Lemma lemma_equalanglessymmetric :
forall A B C a b c,
CongA A B C a b c ->
CongA a b c A B C.