Require Export GeoCoq.Elements.OriginalProofs.proposition_10.
Require Export GeoCoq.Elements.OriginalProofs.proposition_15.
Require Export GeoCoq.Elements.OriginalProofs.lemma_equalanglesreflexive.
Require Export GeoCoq.Elements.OriginalProofs.lemma_angleorderrespectscongruence.
Require Export GeoCoq.Elements.OriginalProofs.lemma_angleorderrespectscongruence2.
Section Euclid.
Context `{Ax:euclidean_neutral_ruler_compass}.

Lemma proposition_16 :
forall A B C D,
Triangle A B C -> BetS B C D ->
LtA B A C A C D /\ LtA C B A A C D.