Require Export GeoCoq.Elements.OriginalProofs.lemma_collinearorder.
Require Export GeoCoq.Elements.OriginalProofs.lemma_ray4.
Section Euclid.
Context `{Ax1:euclidean_neutral_ruler_compass}.

(* Specifications: *)
Lemma lemma_ABCequalsCBA :
forall A B C,
nCol A B C ->
CongA A B C C B A.