Answer:
C) Alternate interior angles theorem.
Step-by-step explanation:
Given : Figure with two line l and m ans alternates interior angle 70°
To find : how can you conclude that lines l and m are parallel.
Solution : We have given that two line l and m ans alternates interior angle 70°.
Two angle are alternate and interior to the line l and m .
Hence they are congruent to each other .
By the alternates interior angle theorem : if two parallel lines are cut by a transversal, then the pairs of alternate interior angles are congruent.
Therefore, C) Alternate interior angles theorem.