## 2.3. Ratio, proportion, and variation

### 2.3.1. Ratio

A ratio (:) is the relation between two like numbers. For example, the ratio 5:7 can be written as a fraction, 5/7, or as division 5 ÷ 7. We read the ratio 5:7 as 5 to 7 or 5 per 7.
Definition of ratio
A ratio is a comparison of two numbers.
A ratio can be expressed by a fraction $(ab)$ or by a colon (:). So, the ratio of two numbers a and b can be written as a:b which is the same as the fraction $ab$, where b  0.
##### Example 1
Reduce the ratio 20:35 to the lowest term.
20:35 = 4/7.
##### Example 2
Reduce the ratio ...

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