(** This is SAS congruence. *)

Lemma l11_49 : forall A B C A' B' C',
CongA A B C A' B' C' -> Cong B A B' A' -> Cong B C B' C' ->
Cong A C A' C' /\ (A <> C -> CongA B A C B' A' C' /\ CongA B C A B' C' A').