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

Lemma lemma_8_2 :
forall A B C,
Per A B C ->
Per C B A.