# Parallel and Perpendicular Lines

Students learn to write the equation of a line given (a) a point on the line and (b) the equation of a line that is parallel or perpendicular to the line. Students learn that parallel lines have the same slope, and perpendicular lines have negative reciprocal slopes. So the first step in the problems in this lesson is to convert the given equation to slope-intercept form and use its slope or the negative reciprocal of its slope along with the given point to write the equation of the line.