RATIO AND PROPORTION

What is Ratio?

A ratio is a comparison of two quantities with same units.

How to write Ratio?

If ‘a’ and ‘b’ are two different quantities with same unit then, we can write the ratio as a : b (read as a is to b).

          A ratio can be written as a fraction; ratios are mostly written in the simplest form.

    It is possible to trace the origin of the word "ratio" to the Ancient Greek Medieval. Writers used the word proprotio ("proportion") to indicate ratio and proportionalities ("proprotionality") for the equality of ratios. Early translators rendered this into Latin as ratio ("reason"; as in the word "rational")

Properties of Ratio:

1    1)      A ratio has no unit. It is a number. For example, the ratio of 8 k.m. to 4 k.m. is written as 8 : 4 = 2 : 1 and not 2 k.m. : 1 k.m.

       2)   The two quantities in a ratio should be of the same unit. The ratio of 4 k.m. to 400 m is expressed as (4 × 1000) : 400 = 4000 : 400 = 10 : 1

       3)      Each number of the ratio is called a term.

       4)      Order of the terms in a ratio cannot be reversed. 5 : 1 and 1 : 5 are not the same.

Ratio and Proportions Questions:

Simplifying ratios of same unit:

1) Simplify the ratio 20 : 5.

 2) Find the ratio of 500 g to 250 g.

3) Madhavi and Anbu bought two tables for ₹ 750 and ₹ 900 respectively. What is the ratio of the prices of tables bought by Anbu and Madhavi?