# Precalculus Examples

, ,

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.

Factor out of .

Cancel the common factors.

Factor out of .

Cancel the common factor.

Rewrite the expression.

Rewrite as .

Move the negative in front of the fraction.

Raise to the power of .

Write the equation of variation such that , replacing with the .