Direct Variation
 Direct Variation |
 Direct Variation |
Direct variation is defined as follows:
The variable y varies directly as x if there is a nonzero constant k such that y = kx. When two variables are related in such a way that the ratio of their values always remains the same, the two variables are said to be in direct variation. This means that as y increases so does x and vice-versa. This equation y = kx is called a direct variation equation. The number k is called the constant of variation.
For example, your first equation in the warm-up was a direct variation equation of y = 5x. For this equation k is equal to 5.