Require Export GeoCoq.Elements.OriginalProofs.lemma_ABCequalsCBA.
Require Export GeoCoq.Elements.OriginalProofs.proposition_04.
Section Euclid.
Context `{Ax:euclidean_neutral_ruler_compass}.

Lemma proposition_05 :
forall A B C,
isosceles A B C ->
CongA A B C A C B.