Two supporting reasons are missing from the proof. complete the proof by dragging and dropping the appropriate reasons into each of the empty boxes. given: m∥n m∠3=120°prove: m∠8=60°  statements           reasons m∥nm∠3=120° given∠5≅∠3 m∠5=m∠3 angle congruence postulatem∠5=120° substitution property of equalitym∠8+m∠5=180° linear pair postulatem∠8+120°=180° m∠8=60° subtraction property of equality  answer choices:   1. angle addition postulate2. alternate interior angles theorem3. substitution property of equality4. alternate exterior angles theorem