📐 Pythagorean Theorem Calculator
Find the hypotenuse or a missing leg of a right triangle using a² + b² = c².
Pythagorean Theorem Calculator
The Pythagorean theorem is one of the most fundamental principles in geometry. It states that in a right triangle, the square of the hypotenuse (the side opposite the right angle) equals the sum of the squares of the other two sides: a² + b² = c².
This calculator lets you find any missing side of a right triangle. Select whether you want to find the hypotenuse (given both legs) or a missing leg (given one leg and the hypotenuse). It also computes the triangle's area and perimeter, and displays a visual diagram.
Frequently Asked Questions
What is the Pythagorean theorem?
The Pythagorean theorem states that in a right triangle, the square of the hypotenuse equals the sum of the squares of the other two sides: a² + b² = c², where c is the hypotenuse (the side opposite the right angle).
Can the Pythagorean theorem work with any triangle?
No. The Pythagorean theorem only applies to right triangles (triangles with one 90° angle). For non-right triangles, you would use the Law of Cosines or Law of Sines instead.
What if my input is negative?
Side lengths must be positive numbers. Negative values are not valid for triangle sides. If you enter a negative value, the calculator will show an error. Simply use the absolute value if you meant a positive length.