What is it?
The Pythagoras Calculator finds the missing side of a right triangle, and its angles, area and perimeter.
Who is it for?
Students, builders checking right angles, carpenters, electricians measuring cable runs, and anyone finding a ladder or diagonal length.
How to use it
Fill in any two sides and leave one empty. Side a and Side b meet at the right angle; Hypotenuse c (longest side) is opposite it. The results include Angle A (opposite a), Angle B (opposite b), Area and Perimeter. The answer appears as you type; there is no Calculate button. Tap Copy result to copy it, or Share on WhatsApp to send it.
No answer?
The hypotenuse must be the longest side. If you enter c smaller than a or b, no right triangle is possible: check which side is which.
Practical uses
- Checking a right angle on site: mark 3 m along one wall and 4 m along the other; the diagonal must be exactly 5 m. Use 6-8-10 for bigger rooms.
- Ladder length: a ladder reaching 4 m up with its foot 1 m from the wall needs to be √17 ≈ 4.12 m long.
- Roof rafters and ramps: the run and the rise give the sloped length.
- TV size: screen diagonal from width and height.
Formula: a² + b² = c².
Worked example
Sides 6 and 8: hypotenuse 10, angles 36.87° and 53.13°, area 24, perimeter 24.
Open the tool: Pythagoras Calculator
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Questions, or an error not listed here?
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