SHAPES, DATA, AND SCHOOL MATH
Pythagorean Theorem Calculator
Use a² + b² = c² to calculate the hypotenuse of a right triangle and review the squared-value check.
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Enter your values and select Calculate. Your result stays on this device.
How it works
Hypotenuse c = √(a² + b²).
Assumptions
The two entered sides are perpendicular legs of a right triangle.
About this calculator
This Pythagorean theorem calculator is designed for the common “find the missing hypotenuse” search. It shows the input legs and squared-value check next to the answer.
How to use it
- Enter the first perpendicular leg.
- Enter the second perpendicular leg in the same unit.
- Calculate the hypotenuse.
- Square the displayed result to verify it against a² + b² when completing school work.
Use case
pythagorean theorem calculator: a clear planning check
Enter two right-triangle legs to calculate c with a² + b² = c² and review the values used in the answer.
Find the hypotenuse of a right triangle from two perpendicular legs and verify the squared-value relationship.
Method and update
Last reviewed: 2026-08-22. This tool performs the stated formula locally in your browser using the values you enter.
Frequently asked questions
What is the Pythagorean theorem?
For a right triangle, the sum of the squares of the two legs equals the square of the hypotenuse: a² + b² = c².
Does this work for every triangle?
No. The relationship applies to right triangles.
What is the hypotenuse of a 3-4-5 triangle?
For legs 3 and 4, the hypotenuse is 5.
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