Consider three angles ∠ABC,∠PQR and ∠LMN. If ∠ABC≅∠PQR and ∠PQR≅∠LMN, then ∠ABC≅∠LMN.
Consider three angles ABC, PQR and LMN. If ∠ABC≅∠PQR and ∠PQR≅∠LMN, then ∠ABC≅∠LMN