Previously, you have investigated direct variation, or a proportional relationship in which the value of the dependent variable changes, or varies, with respect to the value of the independent variable. For a direct variation, the value of the dependent variable increases when the value of the independent variable increases. Also, the value of the dependent variable decreases as the value of the independent variable decreases. The two variables are related by a constant of variation, k, in an equation format.
y = kx
In a direct variation, the independent and dependent variables are related by a constant of variation that is a constant ratio. For example, the situation below can be represented using a direct variation.
There are additional types of variation between two variables. In this lesson, you will investigate situations like the one below, and use tables to represent the relationship between two variables.
