Understanding Angles in Parallel Lines Cut by a Transversal

In a configuration where two parallel lines are cut by a transversal, how do the measures of consecutive interior angles on the same side of the transversal relate?

• They are supplementary.

• They are complementary.

• They are equal.

• They are opposite.

When two parallel lines are cut by a transversal, the sum of the four interior angles on one side of the transversal is: