Math Calculator
Pythagorean Theorem Calculator
Find a missing side of a right triangle using the Pythagorean theorem.
⚠️ Please enter valid positive values. The hypotenuse must be longer than the known side.
Missing Side
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Calculator guide
How this calculator works
How to use this calculator
Choose which side of the right triangle you want to find, then enter the two known side lengths. The calculator finds the missing side.
Formula used
The Pythagorean theorem is a² + b² = c², where c is the hypotenuse of a right triangle.
Example calculation
If side a is 3 and side b is 4, the hypotenuse is √(3² + 4²) = 5.
What the result means
The result is the missing side length of a right triangle.
Frequently asked questions
What is the hypotenuse?
The hypotenuse is the longest side of a right triangle and is opposite the right angle.
Can I use this for any triangle?
No. The Pythagorean theorem applies to right triangles only.
Why must the hypotenuse be longer?
In a right triangle, the hypotenuse is always the longest side.