3-4-5 Right Triangle Hypotenuse
With legs 3 and 4, the hypotenuse is exactly 5 — the classic 3-4-5 Pythagorean triple.
How to use this tool
- Enter side a and side b in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your hypotenuse c and the full breakdown beneath it.
The 3-4-5 right triangle is the most famous Pythagorean triple: a=3, b=4 gives hypotenuse c=5.
Frequently asked questions
- What is the Pythagorean theorem?
- For a right triangle with legs a and b, the hypotenuse c satisfies a² + b² = c². Classic example: 3² + 4² = 9 + 16 = 25 = 5².