The pythagorean theorem is a2+b2=c2
A and B are both legs of the triangle while C is the hypotenuse of the triangle. The basic premise is that when the legs are multiplied by themselves, then added to each other, then it will equal the result of the hypotenuse multiplied by itself. An example would be a triangle with legs 3 and 4. You would plug them into the equation as 32+42. This equals 9+16, which is 25. You then use square roots to figure out the square root of the value that you got from the formula. In this case, it would be the square root of 25, meaning that the hypotenuse length was 5.
