(** * Proposition 34 In parallelogrammic areas the opposite sides and angles are equal to one another, and the diameter bisects the areas. *)
(** # <div style="width:748px;height:397px;display:block" id="applet_container34"></div> # **)

(* Specifications: *)
Lemma prop_34_1 : forall A B D C,
A <> B /\ A <> D /\ B <> D ->
Parallelogram A B D C -> (CongA A B D D C A /\ CongA B D C C A B) /\ (Cong A B D C /\ Cong A C B D).