Section T11_1.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma cong3_conga2 : forall A B C A' B' C' A'' B'' C'',
Cong_3 A B C A' B' C' ->
CongA A B C A'' B'' C'' ->
CongA A' B' C' A'' B'' C''.