Pythagoras’ Theorem Calculator
📐 Trigonometry & Pythagoras. Use the Pythagoras’ theorem formula to find hypotenuse c, side a, side b: pick the value you want, type the others, and the answer updates as you go.
c is the hypotenuse (the longest side, opposite the right angle).
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Hypotenuse c | cm |
| Side a | cm |
| Side b | cm |
Worked example
Find the hypotenuse c when Side a = 3 cm, Side b = 4 cm.
Using c² = a² + b²: Hypotenuse c = 5 cm.
Frequently asked questions
What is the formula for Pythagoras’ theorem?
c² = a² + b². c is the hypotenuse (the longest side, opposite the right angle).
What do the letters stand for, and what units are used?
Hypotenuse c in cm, Side a in cm, Side b in cm.
How do you calculate hypotenuse c?
Put the values into c² = a² + b². For example, with Side a = 3 cm, Side b = 4 cm, hypotenuse c = 5 cm.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (hypotenuse c, side a, side b) and fill in the others: it rearranges the formula for you.
