A proportion is an equation stating that two ratios are equivalent. A relationship that involves a collection of equivalent ratios is called a proportional situation.

In each of these situations, you can see that the relationships are proportional. For each of the data points, the ratios are equivalent.

A rate is a comparison between two quantities. When the denominator of the rate is one, it is called a unit rate.

In this lesson, you will extend what you know about unit rates and look for patterns in graphs of proportional relationships. You will also investigate slope, which is a special characteristic of linear relationships. In a linear relationship, the slope of the line is steepness of the graph of the line. Slope is also described as the ratio of the vertical change to the horizontal change between two points on the line.