# Perpendicular Lines Definition (& Consequence)

- Author:
- Tim Brzezinski

In the applet below, the line that passes through points A & B and the line that passes through points A & C are said to be

**PERPENDICULAR LINES**. Click the red checkbox to show/illustrate what it means for lines to be perpendicular. Then, move/drag points A & B around. 1) Complete the following sentence definition:**Two lines are said to be PERPENDICULAR LINES if and only if _______________________________________________________**. Now, click on the other green checkbox that appeared as well. Move points A & B around again. What do you notice? 2) Complete the following:**If two lines graphed in the coordinate plane are PERPENDICULAR, then their slopes _________________________________________________.**