a^2 + b^2 = c^2....this is the pythagoream theroum (sorry, probably spelled it wrong)....it is used for right triangles. a and b are ur legs of the triangle and c is the hypotenuse. Therefore, the value of a^2 is the value of one of the legs, squared. OR. if u mean this.. a^2 + b^2 = c^2 a^2 = c^2 - b^2