Pythagorean Theorem Calculator
Given legs a and b of a right triangle, compute the hypotenuse: c = √(a² + b²).
Calculator
Use the Pythagorean Theorem Calculator
Result
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Formula
c = √(a² + b²)
Step-by-step
- 1
Enter both legs
The two sides that form the right angle.
- 2
Read the hypotenuse
The longest side of the triangle.
Worked example
Example input: a: 3, b: 4
Result: 5
Related tools
- Triangle Area
Area from base and height.
- Sine Calculator
Trigonometric ratios.
Frequently asked questions
What does the Pythagorean theorem state?
In a right triangle, the square of the hypotenuse equals the squares of the two legs added together: a² + b² = c². Legs of 3 and 4 give c = √(9 + 16) = √25 = 5.
Can this calculator find a missing leg?
It computes the hypotenuse from the two legs. If the hypotenuse is known instead, rearrange the formula yourself: leg = √(c² − a²). For c = 5 and a = 3 that gives √(25 − 9) = 4.
Do the 3-4-5 style shortcuts scale?
Yes — multiplying every side by the same factor keeps the triangle right. 6-8-10 and 9-12-15 are both scaled versions of the 3-4-5 triple.