## Introduction to Ratios

## Opening

# Introduction to Ratios

Look at the picture of stars and triangles and read the following information.

- One way that you can compare the number of stars and the number of triangles is to say that there are 7 more stars than there are triangles. This comparison looks at the difference between two quantities; it uses the operation of subtraction.
- Another way that you can compare the number of stars and the number of triangles is to say that for every 3 triangles there are 10 stars. You can say that the
*ratio*of triangles to stars is 3 to 10 or 3:10. This comparison uses the operation of division. - The value of the ratio of triangles to stars is $\frac{3}{10}$, or 0.3.