**Understanding the Slope of a Line**

The purpose of this applet is to understand the notion of "the slope of a line". Use this applet as follows:

- If you get lost, look in the "MESSAGES" area, you will always be told what to do next. Error messages will also be displayed there.
- Double-click in the grid area to get a first point. Note that once you have selected a point, its coordinates will appear on the left of the applet window, under POINTS.
- Double-click a second time to get a second point. Several things will then happen. First, the coordinates of the new point will appear on the left of the applet window, under POINTS. Then, the quotient rise / run and the value of the slope will be displayed on the left of the applet window, under SLOPE. Finally, the line through the two points will be drawn as well as the triangle symbolizing the rise and the run.
- You can now click on either point and drag it along the line. You will see the point move, the triangle will be redrawn, the coordinates of the point being dragged will be updated. The slope should remain the same.
- If you either click outside the grid area, or try to drag anything other than one of the point, an error message will be displayed.

*This applet was developed by Dr. Philippe B. Laval, at Kennesaw State University.*

*This work was funded in part by: *

*The National Science Foundation grants # GEO-0355224 and # DUE-9952568*

The US Department of Education FIPSE #P116B00178

The US Department of Education FIPSE #P116B00178