Section Angles_5.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma ang_not_lg_null : forall a la lc A B C, Q_Cong la -> Q_Cong lc -> Q_CongA a ->
la A B -> lc C B -> a A B C -> ~ Q_Cong_Null la /\ ~ Q_Cong_Null lc.