Constant of Variation  -  The ratio between two variables in a direct variation or the product of two variables in an inverse variation. In the direct variation equations

= k and y = kx, and the inverse variation equations xy = k and y =

, k is the constant of variation.

Direct Variation  -  A statement of the form

= k or y = kx, where k is a constant of variation.

Inverse Variation  -  A statement of the form xy = k or y =

, where k is a constant of variation.