Answer:
alternate int. <s of parallel lines
Explanation:
We are told that lines r and s are parallel.
Lines r and s are curt by transversal line m.
Theorem:
If two parallel lines are cut by a transversal, then alternate interior angles are congruent.
Angles 2 and 11 are alternate interior angle, so they are congruent.
Answer: alternate int. <s of parallel lines