main menu MyCT
Pythagoras' theorem

     Mathematics index
Geometry (2d) index
Pythagoras' theorem diagram
Pythagoras' theorem states that "the square on the hypotenuse equals the sum of the other two squares. It may be derived by any of a large number of methods.
Fill in the lengths of any two sides (c being the hypotenuse), and this calc will evaluate the third.
Side a is
Side b is
Side c is

Therefore side a is
Therefore side b is
Therefore side c is
Add login to add

Pythagoras' theorem is an extremely important geometric law, which is used in the derivation of many other geometrical solutions. It does not in itself give angles, which may be determined with trigonometry.
The area of the triangle may be determined from the two short sides using the formula area=(1/2)*[side a]*[side b] (a special case of area=(1/2)*base*height, which is general for any triangle). Remember that you only need to fill in two sides, and the third will be calculated.