Require Export GeoCoq.Elements.OriginalProofs.lemma_angleorderrespectscongruence2.
Require Export GeoCoq.Elements.OriginalProofs.lemma_angletrichotomy.
Section Euclid.
Context `{Ax:euclidean_neutral_ruler_compass}.

Lemma proposition_06a :
forall A B C,
Triangle A B C -> CongA A B C A C B ->
~ Lt A C A B.