Use the applet below to explore the relationship between the slopes of parallel and perpendicular line segments.

1. Line segments AB and CD are parallel. Calculate the slope of both of these segments; what relationship do you notice between these rates?
2. Do you think this relationship will always exist between the slopes of parallel lines? Why or why not? (Create another line segment to verify the pattern)
3. Line segments AB and FG are perpendicular. Calculate the slope of both of these segments; what relationship do you notice between these rates?
4. Do you think this relationship will always exist between the slopes of perpendicular lines? Why or why not? (Create another line segment to verify the pattern)