In this section, you will be given several verbal relationships and will learn how to determine the domain and range given a situation.

The perimeter of a regular pentagon is 30 centimeters or less.  Identify the set to describe l, the length of each side of the pentagon.

Check Your Answer

The set includes {0 < l ≤ 6} . The smallest reasonable perimeter is just larger than 0, thus the least side length is just larger than 0 ÷ 5, or 0. The largest reasonable perimeter is 30, thus the greatest side length is 30 ÷ 5, or 6.

The number of tennis balls in n cans can be expressed by the function s = 3n. What is the domain and range of this function?

Check Your Answer

Domain: {0, 1, 2, 3, ...}

The domain is the set of nonnegative integers.

Range: {0, 3, 6, 9,...}

The range is the set of multiples of 3.

As a graph, this relationship would look like this:

This is a graph of discrete data. That is, data that involve only specific values (such as a number of people, or in this case tennis balls).