Algebra/Chapter 3/Percent

3.7: Percentages

Percentages
Percentages are another way of representing rational numbers. Rational numbers can be represented as decimals, fractions or percentages.

Percent, when you actually break the word apart, consists of two words: per and cent. Per is a small but extremely powerful word. It means "to divide". Cent is a Latin word for 100. Percent, then, means "divide by 100".

To convert from a fraction to a percentage, we simply multiply the fraction by 100. For example, $$\frac{1}{4} = (\frac{1}{4} \times 100)\% = 25\%\,$$.

To convert from a decimal to a percentage, we first convert the decimal into a fraction, and then proceed with the approach outlined above. For example, $$0.15 = \frac{15}{100} = (\frac{15}{100} \times 100)\% = 15\%\,$$.