Perpendicular
Definition

Lines are perpendicular if they intersect at right angles (90°) to each other.

If two lines are perpendicular, then their slopes are negative reciprocals.

Perpendicular lines

Explanation
Video does not play in this browser or device. Please try another device or upgrade your browser.
Click to Play

Demonstration
Image only

Instructions text as in global.js
Your browser does not support the canvas element.