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 Description  
 Triangle Inequality:  The sum of the lengths of two sides of a triangle is always greater than the length of the third side.

According to Triangle Inequality, there are certain sets of measurements that cannot be used to form triangles. For example, it is impossible to form a triangle with sides measuring 2, 3, and 6 units, because 2 + 3 < 6.

 

The animation below displays how if given a line segment of three inches, a triangle is not formed until HG + IE are greater than three inches. Notice that when HG + IE equal three inches, they form the line segment HI. This special case is called a degenerate triangle, or in other words no triangle.

 

 

If you know the measures of two sides of a triangle, can you use the Triangle Inequality to determine the greatest and least possible measure of the third side of the triangle?