End T11_1.
Section T11_2.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma cong2_conga_cong : forall A B C A' B' C',
CongA A B C A' B' C' -> Cong A B A' B' -> Cong B C B' C' ->
Cong A C A' C'.