Require Export GeoCoq.Elements.OriginalProofs.proposition_05.
Require Export GeoCoq.Elements.OriginalProofs.lemma_equalanglesNC.
Require Export GeoCoq.Elements.OriginalProofs.lemma_supplements.
Section Euclid.
Context `{Ax:euclidean_neutral_ruler_compass}.

Lemma proposition_05b :
forall A B C F G,
isosceles A B C -> BetS A B F -> BetS A C G ->
CongA C B F B C G.