Ltac ang_instance a A B C :=
assert(tempo_ang:= ex_points_ang a);
match goal with
|H: Q_CongA a |-  _ => assert(tempo_H:=H); apply tempo_ang in tempo_H;
elim tempo_H; intros A ; let tempo_HP := fresh "tempo_HP" in intro tempo_HP; clear tempo_H;
elim tempo_HP; intro B; let tempo_HQ := fresh "tempo_HQ" in intro tempo_HQ ; clear tempo_HP ;
elim tempo_HQ; intro C; intro;  clear tempo_HQ
end;
clear tempo_ang.
Section Angles_2.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

(************************************* Acute angle *****************************************)
Lemma anga_exists : forall A B C, A <> B -> C <> B -> Acute A B C -> exists a, Q_CongA_Acute a /\ a A B C.