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

(* Specifications: *)
Lemma lemma_10_12 :
forall A B C H,
Per A B C -> Per A B H -> Cong B C B H ->
Cong A C A H.