Require Export GeoCoq.Elements.OriginalProofs.proposition_16.
Require Export GeoCoq.Elements.OriginalProofs.lemma_angletrichotomy.
Section Euclid.
Context `{Ax1:euclidean_neutral_ruler_compass}.

Lemma lemma_26helper :
forall A B C D E F,
Triangle A B C -> CongA A B C D E F -> CongA B C A E F D -> Cong A B D E ->
~ Lt E F B C.