If a relationship exists between two values, say *x* and *y*, such that one value, say *y*, is dependent on the other value, *x*, then *x* is referred to as the **independent variable**, and *y* is referred to as the **dependent variable**.

Consider a known relationship, such as the relationship between inches and feet.

There are 12 inches in 1 foot.

What if we want to know the number of inches in a given number of feet?

Then, the number of inches is dependent on the number of feet.

This relationship could be represented by the equation 12*x* = *y*, where *x* is the number of feet, and *y* is the number of inches.

In this situation, *x* is the independent variable and *y* is the dependent variable.

What if we want to know the number of feet in a given number of inches?

Then, the number of feet is dependent on the number of inches.

This relationship could be represented by the equation $\frac{1}{12}$*x* = *y*, where *x* is the number of inches and *y* is the number of feet.

In this situation, *x* is the independent variable and *y* is the dependent variable.

Note that while you will often see the letters *x* and *y* used for the independent and dependent variables, respectively, it is the mathematical language and/or situation which dictates independent and dependent - not the letter used for the variable.

Mathematical relationships are often represented by equations, tables, and/or graphs.

The number of yards times 3 equals the number of feet.

So, an equation which could be used to find the number of feet based on the number of yards is 3*y* = *f*.