Require Export GeoCoq.Meta_theory.Decidability.equivalence_between_decidability_properties_of_basic_relations.
Section T5.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma cong3_symmetry : forall A B C A' B' C' : Tpoint , Cong_3 A B C A' B' C' -> Cong_3 A' B' C' A B C.