Is there a more rigid definition for perpendicularity? A line of the form y = C has a slope of 0. There is no negative reciprocal for 0, but a line of the form x = C is still perpendicular.

Parallel lines never intersect, and perpendicular lines intersect at a 90 degree angle. Learn how to identify parallel and perpendicular lines.

Parallel lines are lines that never intersect, and they form the same angle when they cross another line. Perpendicular lines intersect at a 90-degree angle, forming a square corner. We …

The slopes of parallel lines are equal, and the slopes of perpendicular lines are opposite reciprocals. This is a worked example of determining whether given lines are parallel or …

Review the basics of parallel and perpendicular lines. Identify and draw parallel and perpendicular lines in some practice problems.

Given line A and point P, Sal finds the equation of the line perpendicular to A that passes through P. Created by Sal Khan and Monterey Institute for Technology and Education.

In this video, we first derive the conditions for parallel and perpendicular lines. We then apply these conditons to prove that given lines are parallel/perpendicular.

Unit 1: Lines About this unit Learn what lines, line segments, and rays are and how to use them.

Since there's no "change in x" (but y can take on any value), the line is vertical. In order to write its equation, all we need to know is where it crosses the X-axis and we call that point c, giving us …

Given points that two lines go through or the graph of each line, classify the lines as parallel, perpendicular, or neither.