Pythagorean Calculator
Enter any two sides of a right triangle — the third is solved with the a²+b²=c² working shown step by step.
Fill in any two sides; leave the unknown one blank. The hypotenuse c is the side opposite the right angle.
All sides: a = —, b = —, c = —
Diagram
The gold label marks the side you asked for.
Steps
How to use the Pythagorean calculator
- Enter two sides. The two legs, or one leg and the hypotenuse — leave the unknown blank.
- Press Solve. The missing side appears with every substitution step of a²+b²=c².
- Read the bonus stats. The two acute angles and the area come free with every solve.
- Check the diagram. Your solved side is highlighted in gold, true to scale.
Frequently asked questions
How do I solve for a missing side?
Enter any two sides and leave the third blank. The tool applies a² + b² = c², rearranged for the missing side, and shows every substitution step.
What if the hypotenuse is shorter than a leg?
That's impossible — the hypotenuse is always the longest side of a right triangle. You'll get an error asking you to check your numbers.
How are the angles found?
With inverse tangent: the angle opposite leg a is arctan(a/b), and the other acute angle is 90° minus that.
What is the area of the right triangle?
Half the rectangle the legs make: A = a × b / 2.
Does it work for non-right triangles?
No — the Pythagorean theorem only applies to right triangles. Use the Triangle Solver for SSS, SAS, ASA, and AAS cases.
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