Investigating Geometry with GeoGebra

Henrico County Public Schools

Triangle Inequality

READ the instruction below and INTERACT with the GeoGebra applet on the right.

  1. Note that AB = 8, AC = 3 and BC = 5 and you have a straight line.

  2. Next, look at the values below the figure. What do you notice? What relationships exist?

  3. Move points A and B, what changes?

  4. Now, move the AB slider and observe the figures. Try moving the other sliders. Can you describe what happens?

  5. What are relationships between the three expressions that must occur to form a triangle?
Sorry, the GeoGebra Applet could not be started. Please install Java 1.4 (or later) to use this page.