direct variation

When two variable quantities have a constant (unchanged) ratio, their relationship is called a direct variation.
It is said that one variable "varies directly" as the other.

The constant ratio is called the constant of variation.

The formula for direct variation is y = kx,
where k is the constant of variation.
"y varies directly as x"
Solving for k:
(y = numerator; x = denominator)

Example:
The weekly salary a woman earns, S, varies directly as the number of hours, h, which she works. Express this relation as a formula.

Answer: S = hk or (where k is the constant)

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