Parallel Lines and Perpendicular Lines

Slopes Of Parallel Lines

In coordnate geometry, two lines are parallel if their slopes (m) are equal.

For example: The line is parallel to the line . Their slopes are both the same.

Slopes Of Perpendicular Lines

In the coordinate plane, two lines are perpendicular if the product of their slopes (m) is –1.

For example: The line is perpendicular to the line y = –2x – 1. The product of the two slopes is

The following video shows how we can determine whether a given pair of lines are parallel or perpendicular.

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