Percentage Formula

Percentage and its application:

A fraction with denominator 100 is called a per cent. Per cent is an abbreviation for the latin word "Percentum" meaning "per hundered" or "hundredhs" and it denoted by symbol%

Note: a fraction with denominator 10 is called as decimal

Since per cent is a form of fraction, we can express per cent as fractions (or decimals) and vice - versa

Conversion of fraction into percentage

To convert a fraction into a percentage, multiply the fraction by 100 and put % sign.

Example 1 Convert the following fraction into percentage:

i) 1/2          ii) 3/4            iii) 4/5           iv) 7/8

Solution:

i) 1/2 ---> 1/2x100 = 50%

ii) 3/4---> 3/4x100 = 75%

iii) 4/5---> 4/5x100 = 80%

iv) 7/8---> 7/8x100= 87.5%

Conversion of a Percentage into a Fraction:

To convert a percentage into a fraction, replace the % sing with 1/100 and reduce the fraction to simplest form.

Example 2  Express the following percentage as fraction

i) 20%      ii) 30%         iii) 45%       iv)5 1/8%     v)155%

Solution:

i) 20% = 20/100 = 1/5

ii) 30% = 30/100 = 3/10

iii) 45% = 45/100 = 9/20

iv) 5 1/8% = 41/8x100 = 41/800

v) 155% = 155/100 = 31/20 = 1 11/20

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