Pythagorean Theorem Calculator
Leave exactly one field blank to calculate its value. Uses: A² + B² = C²
Side A
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Side B
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Hypotenuse C
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Pythagorean Triple
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Show the math
Enter values to see the worked formula.
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What Your Result Means
- Side A & B: The two shorter sides of a right triangle (the legs).
- Hypotenuse C: The longest side of a right triangle, opposite the 90-degree angle.
- Pythagorean Triple: "Yes" means all three sides are whole numbers (integers), which is special in mathematics.
How This Calculator Works
The Pythagorean theorem states that in a right triangle, A² + B² = C², where C is the hypotenuse. This calculator uses that formula to find the missing side when you provide any two sides. Enter exactly two sides and leave one blank, and the calculator solves for the unknown using algebra.
Quick Questions
What's a Pythagorean triple?
A set of three whole numbers that satisfy A² + B² = C². Examples: 3-4-5, 5-12-13, and 8-15-17.
What if my triangle doesn't have a 90-degree angle?
This calculator only works for right triangles (with one 90° angle). For other triangles, use the Law of Cosines.
Why do I get decimal results?
Most combinations of side lengths don't produce whole numbers. Decimals are accurate; only integer results form Pythagorean triples.
Sources
- Wolfram MathWorld - Pythagorean Theorem (Mathematical definition and history)
- Wikipedia - Pythagorean Theorem (Theorem explanation and applications)
- Wikipedia - Pythagorean Triple (Integer solutions)
Method & review
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.