Parallel lines are a fixed distance apart and will never meet, no matter how long they are extended. Perpendicular lines are created when a vertical and horizontal line meet.

Horizontal lines run left to right, parallel to the horizon, with slope 0 and equation y = k. Vertical lines run top to ...

Parallel lines are a fixed distance apart and will never meet, no matter how long they are extended. Perpendicular lines are created when a vertical and horizontal line meet.