proposition: Lemma sams2_suma2__conga123 : forall A B C A' B' C' D E F G H I, SAMS A B C D E F -> SAMS A' B' C' D E F -> SumA A B C D E F G H I -> SumA A' B' C' D E F G H I -> CongA A B C A' B' C'.
proof: Proof. intros A B C A' B' C' D E F G H I Hisi Hisi' Hsuma Hsuma'. apply (sams2_suma2__conga456 D E F _ _ _ _ _ _ G H I); SumA. Qed.
imports: GeoCoq.Tarski_dev.Ch11_angles