is the power, and is the constant of or constant of We say f(x) varies as the ath power of x, or f(x)is to the ath power of x. Common Formulas from Geometry and Science Name Formula Power Constant of Variation Circumference C = 2nr Area of a circle A = nr2 Force of Gravity k F = dz k Boyle's Law V = P Writing and Analyzing Power Functions EX #1: In the formula d = = gt2 , state the power and the constant of variation