Basic Mathematics for College Students

506 Chapter 6 Percent

4 Write decimals as percents.

To write a percent as a decimal, we drop the % symbol and move the decimal point 2

places to the left. To write a decimal as a percent, we do the opposite: we move the

decimal point 2 places to the right and insert a % symbol.

Writing Decimals as Percents

To write a decimal as a percent, multiply the decimal by 100 by moving the

decimal point 2 places to the right, and then insert a % symbol.

EXAMPLE (^9) Geography Land areas make up 0.291 of Earth’s surface.
Write this decimal as a percent.
StrategyWe will multiply the decimal by 100 by moving the decimal point 2
places to the right, and then insert a % symbol.
WHYTo write a decimal as a percent,we reverse the steps used to write a percent
as a decimal.
Solution
Multiply 0.291 by 100 by moving the decimal point 2
places to the right, and then insert a % symbol.
0.291, written as a percent, is 29.1%

29.1%

0.2910 29.1%

Self Check 9

Write 0.5343 as a percent.

Now TryProblems 71 and 75

5 Write fractions as percents.

We use a two-step process to write a fraction as a percent. First, we write the fraction

as a decimal. Then we write that decimal as a percent.

Fraction  decimal  percent

Writing Fractions as Percents

To write a fraction as a percent:

1. Write the fraction as a decimal by dividing its numerator by its
   denominator.


2. Multiply the decimal by 100 by moving the decimal point 2 places to the
   right, and then insert a % symbol.

EXAMPLE (^10) Television The highest-rated television show of all time
was a special episode of MAS*Hthat aired February 28, 1983. Surveys found
that three out of every five American households watched this show. Express the
rating as a percent.
StrategyFirst, we will translate the phrase three out of every fiveto fraction
form and write that fraction as a decimal. Then we will write that decimal as a
percent.
Self Check 10
Write 7 out of 8 as a percent.
Now TryProblem 79

Success Tip When percents that are greater than 100% are written as
decimals, the decimals are greater than 1.0. When percents that are less than
1% are written as decimals, the decimals are less than 0.01.