Given: AB || DC ∠A ≅ ∠D Prove: ΔABC ≅ ΔDCB Triangles A B C and D C B share common side C B. Angles C D B and C A B are congruent. Sides C D and A B are parallel. Isabelle proves that the triangles are congruent by using the parallel lines to determine a second set of angles are congruent. What statement and reason could she have used? ∠ABC ≅ ∠BAC; corresponding angles of parallel lines are congruent. ∠CAB ≅ ∠DCB; alternate interior angles of parallel lines are congruent ∠ABC ≅ ∠DCB; alternate interior angles of parallel lines are congruent ∠ACD ≅ ∠ABD; corresponding angles of parallel lines are congruent.