If two ratios are equal, we say they are in proportion

Example:

    1/2 & 3/6

10.jpg

3 ÷ 2 = 1/2

6 ÷ 2 = 1/2

 

∴ 1/2 = 3/6

i.e.

  1 : 2 = 3 : 6

 

We also write it as

17.jpg

 

And we say that,

  1, 2, 3, 6 are in proportion

 

Note:

When we write 4 numbers in proportion

1 , 2, 3, 6

1 , 6 are called extreme terms

2 , 3 are called middle terms

 

Are 10, 20, 40, 80 in proportion?

   

Ratio of 10 & 20 = 10/20

= 1/2

 

= 1 : 2

Ratio of 40 & 80 = 40/80

= 4/8

= 1/2

= 1 : 2

∴ 10 : 20 = 40 : 80

So, 10, 20, 40, 80 are in proportion

  1. Chapter 12 Class 6 Ratio And Proportion
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1 : 2 ∷ 3 : 6 Ratio Proportion

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.