Triangle inequality theorem

What you'll learn

1. State the triangle inequality theorem: the sum of any two sides must be greater than the third side
2. Determine whether three given lengths can form a triangle
3. Find the range of possible values for the third side when two sides are known
4. Solve SAT multiple-choice problems of the form "which of the following could be the length of the third side?"

Prerequisites

• Triangle angle sum and exterior angle theorem