Vocabulary

The hypotenuse is the side opposite of the right angle. It is the longest side.​

The legs are the two sides that form the right angle.​

Concept

Identify the length of the hypotenuse using the Pythagorean Theorem.

Rules

1. Use the Pythagorean Theorem to find the length of the hypotenuse.
2. Substitute the given values in the formula a² + b² = c²
3. Solve using order of operations.
4. Select the correct answer choice.

Example

If a right triangle has legs that measure 5 and 12, what is the length of the hypotenuse?

Solution

The lengths of the legs are substituted into the Pythagorean Theorem formula for a and b. 

a² + b² = c²

5² + 12² = c²

25 + 144 = c²

c² = 169

c = √169 = 13

Pre-requisite Skills

Pythagorean Theorem (8.6.5)