Two parallel lines cut by a transversal form 8 angles.
There are unique properties and names for pairs of these angles.
Click on a term to view the angle pairs. What do you think is the definition of each angle pair?

1. When are the blue and yellow lines parallel to each other? What is true about their slopes?
2. What do you notice about the measures of the Alternating Interior and Exterior Angles when
the two lines are parallel?
3. What is true about the measures of the Same side interior angles when the lines are parallel?
4. What condition must be true in order for the Same side exterior angles to be supplementary?
5. What is true about the lines when the alternating interior angles are not congruent?