Section T11_2.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.
(** This is exterior angle theorem *)

Lemma lta_trans : forall A B C A1 B1 C1 A2 B2 C2,
LtA A B C A1 B1 C1 ->
LtA A1 B1 C1 A2 B2 C2 ->
LtA A B C A2 B2 C2.