Parallel and Perpendicular Lines
Rule 1: If two lines have the same slope, then they are parallel.
In other words, the slopes of parallel lines are equal.
Note that two lines are parallel if there slopes are equal and they have different y-intercepts.
Rule 2: If the product of the slopes of two lines is -1, then the lines are perpendicular.
In other words, slopes of perpendicular lines are negative reciprocals of each other.
Learn more about parallel and perpendicular lines by reading the explanation below.
Parallel and Perpendicular Lines
Practice: Answer the following exercises about parallel and perpendicular lines.