The same side interior angles are NOT congruent. They are supplementary. ... The same side interior angles can be congruent only when each angle is equal to a 90 degree because then the sum of the same side interior angles is equal to 180 degrees.

Are all interior angles equal?

When two parallel lines are crossed by a transversal, the pair of angles formed on the inner side of the parallel lines, but on the opposite sides of the transversal are called alternate interior angles. These angles are always equal.

Are same side interior angles supplementary?

Same side interior angles are always supplementary, meaning that the sum of their measures if 180°.