Perpendicular Lines - Quick Intro

WARM UP: In the applet below, the purple line and the brown line are said to be perpendicular lines. Move the white points around a bit, then answer the question that appears below the applet.

Perpendicular Lines

Question:

What does it mean for two lines to be perpendicular? Without looking up the definition on another tab in your browser, write a sentence definition in the response box below. Be specific in your description!