How to Use the Pythagorean Theorem Calculator
The Pythagorean theorem a² + b² = c² describes the relationship between the three sides of any right triangle. Legs a and b form the right angle; hypotenuse c is the longest side opposite it. Select which side to find, enter the other two, and get the answer instantly.
- Find hypotenuse (c): c = √(a² + b²)
- Find leg (a): a = √(c² - b²)
- Find leg (b): b = √(c² - a²)
Classic example: the 3-4-5 triangle. Enter a=3 and b=4 → c = √(9+16) = √25 = 5. This ratio is the most famous Pythagorean triple.
Frequently Asked Questions
That is geometrically impossible. The hypotenuse is always the longest side. The calculator will show an error if your inputs violate this rule.
Yes. Decimal inputs are fully supported and results are shown to four decimal places.
Construction diagonal checks, straight-line distances on maps, game character movement, and signal calculations in electronics all rely on this theorem.