Section T7_1.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.
(** This corresponds to l7_8 in Tarski's book. *)

Lemma l7_16 : forall P Q R S P' Q' R' S' A,
Midpoint A P P' -> Midpoint A Q Q' ->
Midpoint A R R' -> Midpoint A S S' ->
Cong P Q R S -> Cong P' Q' R' S'.