Parallel, Perpendicular and Skew Lines

Parallel lines are lines in a plane that never meet; they are always the same distance apart and have the same slope.

Perpendicular lines are lines that intersect at a right angle (90 degrees).

Skew lines are lines that do not intersect and are not parallel; they exist in different planes.

If two lines are parallel, their slopes are equal.

If two lines are perpendicular, the product of their slopes is -1.

When a transversal crosses parallel lines, it creates corresponding angles that are equal.

The distance between parallel lines remains constant, which is a key characteristic of parallelism.