Consecutive Interior Angles
When two lines are crossed by another line (called the Transversal): The pairs of angles on one side of the transversal but inside the two lines are called Consecutive Interior Angles. In this example, these are Consecutive Interior Angles:
To help you remember: the angle pairs are "Consecutive" (they follow each other), and they are on the "Interior" of the two crossed lines |
Parallel LinesIf the two lines being crossed are Parallel Lines, then the Consecutive Interior Angles add up to 180°. (Click on "Consecutive Interior Angles" to have them highlighted for you.) |
Language Note: Also called Co-Interior Angles in the UK and Australia