The Pythagorean Theorem is an equation that shows the relationship between the three sides of a right triange.
This is an image of the theorem. Just so we have some terms down, sides a and b are reffered to as the legs, and side c is the hypotenuse. The equation at the bottom is the actual theorem- in a right triangle, the length of a2 and the length of b2 added together will equal the length of c2, or a2 + b2= c2. This theorem is useful for finding the other sides of the right triangle when one is missing. THIS THEOREM IS ONLY FOR RIGHT TRIANGLES. It does not apply to any other kind of triangle.