Triangle Inequality - One Triangle

Side Length Relationships

Triangle Sides Relationships

In the applet above, one side of triangle ABC is given a set length. AB is 3. The length of AC can be adjusted using the slide at the top. The measure of CB is displayed. As you adjust the length of AC, what do you notice?

Possible Triangles

In the applet above, there are two sets of segments given. Move the segments around. *Can the green segments make a triangle? *Can the pink segments make a triangle? Use the distance tool. Which segments can make a triangle? Which segments cannot make a triangle? *Do you notice a connection between the first applet and the above applet?


In the applet above, you are given two sides of a possible triangle. The two side lengths are 4 units and 12 units in length. Make a hypothesis about the range of possible side lengths for the third side. *Test your hypothesis by making segments for the third side of the triangle.