Parallel and Perpendicular Lines. Lines & Angles Section 3-1. Lines & Angles. Parallel Lines ( ll ) - are coplanar and do not intersect. Perpendicular Lines (⏊) – intersect at 90 ํ angles . Skew Lines – are not coplanar. Skew lines are not parallel and do not intersect.
Lines & Angles
What are some examples of perpendicular lines??