Given m∥n .

What theorem or postulate justifies this statement?

∠1≅∠5


alternate exterior angles theorem

linear pair postulate

vertical angles theorem

alternate interior angles theorem

corresponding angles postulate
The figure shows two parallel lines labeled m and n. Line m is above line n. A transversal labeled t intersects both parallel lines. The intersection of transversal t with line m forms angles 1, 2, 3, and 4. Angle 1 is above line m and to the left of transversal t. Angle 2 is above line m and to the right of transversal t. Angle 3 is below line m and to the right of transversal t. Angle 4 is below line m and to the left of transversal t. The intersection of transversal t with line n forms angles 5, 6, 7, and 8. Angle 5 is above line n and to the left of transversal t. Angle 6 is above line n and to the right of transversal t. Angle 7 is below line n and to the right of transversal t. Angle 8 is below line n and to the left of transversal t.