Why use this calculator
The Pythagorean theorem is fundamental in geometry, construction, navigation, and many real-world applications involving right triangles.
How to use it
Select which side you want to solve for, enter the known sides, and calculate. When solving for the hypotenuse, enter both legs. When solving for a leg, enter the hypotenuse and the other leg.
The formula
a² + b² = c², where c is the hypotenuse. Solving: c = √(a² + b²), a = √(c² - b²), b = √(c² - a²).
Worked examples
Sides 3 and 4
Hypotenuse = 5
Sides 5 and 12
Hypotenuse = 13
When people use it
- Construction and carpentry
- Navigation and distance calculations
- Physics problems
- Computer graphics
Tips
- Common Pythagorean triples: 3-4-5, 5-12-13, 8-15-17, 7-24-25
- Multiples of triples also work: 6-8-10, 9-12-15
Questions people ask
- Does this work for non-right triangles?
- No, the Pythagorean theorem only applies to right triangles. For other triangles, use the Law of Cosines: c² = a² + b² - 2ab·cos(C).