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Pythagorean Theorem Calculator - Right Triangle Solver

Free Pythagorean theorem calculator. Find the missing side of a right triangle using a² + b² = c². Calculate hypotenuse or leg instantly.

Pythagorean Theorem Calculator

a² + b² = c²

One leg of the right triangle.

Other leg of the right triangle.

The longest side, opposite the right angle.

Result

Enter your values to see results

and click the "Calculate" button

What is the Pythagorean Theorem?

The Pythagorean theorem states that in a right triangle, the square of the hypotenuse (the side opposite the right angle) equals the sum of squares of the other two sides. This fundamental theorem is expressed as a² + b² = c², where c is the hypotenuse.

How to Use This Calculator

  1. Enter any two sides of the right triangle
  2. Leave the unknown side blank
  3. Click Calculate to find the missing side
  4. View area and perimeter as bonus results

Pythagorean Formula

a² + b² = c²

To find c: c = √(a² + b²). To find a: a = √(c² - b²). To find b: b = √(c² - a²).

Frequently Asked Questions

What is a right triangle?
A right triangle has one angle exactly 90 degrees. The side opposite to this right angle is called the hypotenuse and is always the longest side.
What are Pythagorean triples?
Pythagorean triples are sets of three whole numbers that satisfy a² + b² = c². Common examples: (3,4,5), (5,12,13), (8,15,17), (7,24,25).
Can I use this for non-right triangles?
No, the Pythagorean theorem only works for right triangles. For other triangles, use the Law of Cosines: c² = a² + b² - 2ab·cos(C).

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