Algebra 1 Notes Lesson 5-6: Parallel and Perpendicular Lines
Vocabulary Parallel Lines
Parallel Lines in a Coordinate Plane Two nonvertical lines are parallel if they have the same slope. All vertical lines are parallel.
Example 1 Write the slope-intercept form of an equation for the line that passes through (4, –2) and is parallel to the graph of
Vocabulary Parallel Lines Perpendicular Lines
Perpendicular Lines in a Coordinate Plane Two nonvertical lines are perpendicular if the product of their slopes is –1. That is, the slopes are opposite reciprocals of each other. Vertical lines and horizontal lines are also perpendicular.
Example 2 Write the slope-intercept form of an equation for the line that passes through (4, –1) and is perpendicular to the graph of