Pythagorean Theorem Calculator
Find any missing side of a right triangle using a² + b² = c² — enter any two sides and get the third with full working shown.
What Does This Tool Do?
Find any side of a right triangle — enter two sides and leave the third blank. Works for finding the hypotenuse (c) or either leg (a or b) using the Pythagorean theorem a² + b² = c².
Key Features
Any Side
Find a, b or c — whichever is missing.
Area
Triangle area calculated as a bonus.
Visual Diagram
Labelled right triangle shown.
Working Shown
Full formula with substituted values.
How to Use
- Enter any two of the three sides.
- Leave the side you want to find blank.
- Click Calculate.
Frequently Asked Questions
What is the Pythagorean theorem?▾
a² + b² = c², where a and b are the two legs of a right triangle and c is the hypotenuse (the side opposite the right angle).
Which side is the hypotenuse?▾
The hypotenuse (c) is always the longest side and is always opposite the right angle (90° angle).
Can I find a leg if I know the hypotenuse?▾
Yes: a = √(c² − b²). Enter the hypotenuse and one leg, leave the other leg blank.