- Books Name
- CBSE Class 6 Mathematics Book

- Publication
- Param Publication

- Course
- CBSE Class 6

- Subject
- Mathmatics

**Proportion**

An equality of two ratios is called a proportion. If two ratios are equal, we say that they are in proportion and use the symbol ‘::’ or ‘=’ to equate the two ratios.

For the example, we can say 3, 10, 15 and 50 are in proportion which is written as 3 : 10 :: 15 : 50 and is read as 3 is to 10 as 15 is to 50 or it is written as 3 : 10 = 15 : 50

In the proportion, the first and the fourth terms are called the extremes or extreme terms. The second and the third terms are called the middle terms or means.

In case of proportion, we can say that the product of the extreme terms = the product of the middle terms.

*∴* Product of extremes = product of means

**Ex.2** Do the ratios 15 cm to 2 m and 10 sec to 3 minutes form a proportion?

**Sol. **Ratio of 15 cm to 2 m = 15 : 2 × 100 (1 m = 100 cm) = 3 : 40

Ratio of 10 sec to 3 min = 10 : 3 × 60 (1 min = 60 sec) = 1 : 18

Since, 3 : 40 1 : 18, therefore, the given ratios do not form a proportion.*∷*