Find c
a=3, b=4c = 5
Pythagorean Theorem Calculator
Use this free Pythagorean theorem calculator to solve for the hypotenuse or a missing leg of a right triangle with steps and examples.
Unit-aware inputs Formula note Example numbers Tab-only history
Hypotenuse c5 cm
- Leg a
- 3 cm
- Leg b
- 4 cm
- Hypotenuse c
- 5 cm
Steps
- Use the Pythagorean theorem for right triangles: a^2 + b^2 = c^2.
- Solve c by taking sqrt(a^2 + b^2).
- The missing side is 5 cm.
How to use the Pythagorean Theorem Calculator
- Choose whether you need the hypotenuse, leg a, or leg b.
- Enter the two known side lengths of the right triangle.
- Press Calculate side to solve the missing side with a^2 + b^2 = c^2.
- Use examples, recent answers, or copy the result while checking right-triangle work.
What people use it for
Find the hypotenuse when both legs are known.
Find a missing leg when one leg and the hypotenuse are known.
Check right triangle side lengths for homework.
Copy formula steps for Pythagorean theorem practice.
Quick examples
Find a
b=12, c=13a = 5
Find b
a=8, c=17b = 15
Need the guide or a nearby tool?
Need a slower walkthrough, a related calculator, or the full library? These links keep you close to the task you started.
- How to use the Pythagorean Theorem Calculator See slower examples, input meanings, formula notes, result limits, and mistakes to avoid.
- Calculators Browse related calculators and utilities in the same category.
- Calculator and utility guides Find more guides that use real tool inputs and example numbers.
- All free tools Search every live tool, converter, calculator, AI helper, and browser utility.
Frequently asked questions
Quick answers about formulas, units, valid measurements, examples, copying, and private in-browser history.
What formula does the calculator use?
It uses the Pythagorean theorem: a^2 + b^2 = c^2, where c is the hypotenuse of a right triangle.
Can it solve for a missing leg?
Yes. If you know the hypotenuse and one leg, it subtracts the known leg squared from the hypotenuse squared, then takes the square root.
What do the main Pythagorean Theorem Calculator inputs mean?
The main inputs are the numbers, operation, mode, or known values the calculator needs. Keep units consistent, enter percentages the way the page label shows, and use the examples as a quick check before trusting the answer.
How should I read the Pythagorean Theorem Calculator answer?
Read the headline answer, then check the supporting lines and examples to understand how the calculator got there. If one input changes, rerun the tool and compare the new answer instead of guessing.
What should I double-check before trusting the Pythagorean Theorem Calculator?
Check units, signs, rounding, and the selected mode before copying the answer. If the number feels weird, rerun one of the examples first, then put your own values back in slowly.
Does the Pythagorean theorem work for every triangle?
No. It only applies to right triangles with one 90-degree angle.
What if the hypotenuse is shorter than a leg?
That input is invalid for a right triangle. The hypotenuse must be the longest side.
Should I use the Right Triangle Calculator instead?
Use this tool when you only need a missing side. Use the Right Triangle Calculator when you also want area, perimeter, and angles.
Is my Pythagorean history private?
Yes. Recent Pythagorean answers stay only in the current browser tab while you use the page. They are not sent to a server.