- Books Name
- CBSE Class 7 Mathematics Book

- Publication
- Param Publication

- Course
- CBSE Class 7

- Subject
- Mathmatics

** Ratio and Proportion**

**Ratio**

A ratio is the comparison of two or more quantities of same kind using division or we can define ratio of two quantities a and b of the same kind in the same units as a fraction which is written generally as a : b (read as ‘a’ is to ‘b’). In the ratio a : b, ‘a’ is called the first term or antecedent and ‘b’ is called the second term or consequent.

**RATIO IN SIMPLEST FORM OR LOWEST TERM**

A ratio is said to be in its simplest form or lowest terms when its terms do not have common factor except 1.

**Note :**

1. Ratio only exists between quantities of same kind :

(i) There exists no ratio between the height of a child and the weights of a child.

(ii) We cannot write a ratio between the age of a student and the marks obtained by the student.

2. To find a ratio between the quantities of same kind, quantities should be expressed in same units.

3. Ratio has no unit.

**(I) Comparison of Ratio: ** Two ratios can be compared by converting them to like fractions. If the two fractions are equal, we say that two given ratios are equivalent.

** Illustration 1 **

Express the ratio 36 : 81 in the simplest form.

** Solution **

H.C.F. of 36 and 81 is 9