### Home > CC3 > Chapter 9 > Lesson 9.1.3 > Problem 9-33

9-33.

Based on the given information, determine which pairs of lines, if any, are parallel. If none are necessarily parallel, write “none.”

Alternate interior angles and corresponding angles have equal measure only if the lines cut by the transversal are parallel.

Conversely, if the angle measures are equal, the lines must be parallel.

These are alternate interior angles.

These are corresponding angles.

andIn the diagram below, the measures of

and are equal. Do any two lines look parallel? Vertical angles always have equal measure.

andand are supplementary. would be supplementary to if was equal to .