When three variable quantities have a constant ratio, their relationship is called a direct variation. It is said that one variable varies directly as the other two vary. The formula for direct variation is , where is the constant of variation.
Solve the equation for , the constant of variation.
Replace the variables , , and with the actual values.
Raise to the power of .
Multiply by .
Divide by .
Write the equation of variation such that , replacing with the .