A ratio is a number that relates two quantities or measures within a given situation in a ** multiplicative relationship**.

Ratios show comparisons of a ** part to a whole**. For example, the number of girls in a class to number of students in a class. It is much like fractions. So fractions are also ratios. Percentages are also ratios. Probabilities are also ratios. Rates are also ratios.

Ratios show comparison of one part of a whole to another part of the same whole. Example: ratio can show the number of girls in a class to number of boys in the same class.

Relationship between two units of measure are also rates or ratios. Example, inches per foot.

Proportion is a statement of equality between two ratios.

Example 1: If 4 boats can carry 20 passengers, then 2 boats of the same size will carry 10 passengers. And one boat can carry 5 passengers.

A ratio compares two numbers or groups of objects.

Ratios can be written in the following ways: 4 to 20, 4:20, and 4/20. They are read as “4 to 20”.

Each ratio show the same comparison.

**Exercise 2.**

Danny bought a pineapple that weighed 2 pounds. The vendor sold her the pineapple for $12.00 dollars. How much would two pineapples that weigh a total of 5 pounds cost?

$12.00 for 2 pounds of pineapple

12: 2

## Practice questions

- Sarah works for $24 per hour. If she works for 4 hours every day from Monday to Friday. How much does she earn? Click here to view answer.
- Mark bought 6 apples for $36. His sister bought 4 for $24. Who paid the most for the apples? click here to view the answer.