Triangle Side Lengths Worksheet

Triangle Side Lengths

Read each question carefully and answer to the best of your ability. Remember the Triangle Inequality Theorem: The sum of the lengths of any two sides of a triangle must be greater than the length of the third side.

1. Which set of side lengths CANNOT form a triangle?

2. If two sides of a triangle measure 5 inches and 12 inches, which of the following could be the length of the third side?

3. The sum of the lengths of any two sides of a triangle must be   than the length of the third side.

4. If a triangle has sides of length 8 cm and 15 cm, the third side must be between   cm and   cm.

5. A triangle has side lengths of 10 units and 10 units. What are the possible whole number lengths for the third side?

6. Draw a triangle with side lengths 4 cm, 6 cm, and 7 cm. Label the sides.

7. A triangle can have side lengths of 1 cm, 2 cm, and 3 cm.

8. If two sides of a triangle are equal, then the third side must also be equal to them.

9. Consider a triangle with two sides measuring 9 meters and 13 meters. Let 'x' represent the length of the third side. Write an inequality that describes the possible values for 'x'.

10. Sarah is building a triangular garden. She has two fences that are 10 feet and 18 feet long. What is the range of possible lengths for the third fence?