Mathematics · Geometry
Pythagorean Theorem Calculator
Find the hypotenuse of a right triangle from its two legs.
Inputs and results stay in this browser. Change one value at a time to explore the relationship.
Calculation steps
- Square the legs: 3² = 9; 4² = 16.
- Add: 9 + 16 = 25.
- Take the square root: c = 5.
Definition and formula
For a right triangle, the square of the hypotenuse equals the sum of the squares of the legs.
c = √(a² + b²)
Worked example
Legs 3 and 4 produce hypotenuse √(9 + 16) = 5.
Common mistake
This relationship applies only to right triangles, and c is always the hypotenuse.
How to learn with this calculator
Begin with the worked example, then change one value while keeping the others fixed. Compare the new result and calculation steps to identify which part of the formula changed.
Clear answers
Frequently asked questions
What does the Pythagorean theorem do?
Find the hypotenuse of a right triangle from its two legs.
How does the Pythagorean theorem work?
The calculator applies c = √(a² + b²). For a right triangle, the square of the hypotenuse equals the sum of the squares of the legs.
What can I learn from the Pythagorean theorem?
It connects the mathematical rule to your chosen numbers and shows each calculation step. Change one input at a time to see how the result responds.
Does MW SysArc receive or store what I enter?
No. The calculation runs locally in your browser. MW SysArc does not receive or store your calculation inputs.
How should I use the result?
Use the steps to understand the method, then verify important school or professional work using the notation and rounding rules required in your setting.
Last reviewed 2026-07-14. Calculations tested 2026-07-14.