Basic Mathematics for College Students

504 Chapter 6 Percent

3 Write percents as decimals.

To write a percent as a decimal, recall that a percent can be written as a fraction with

denominator 100 and that a denominator of 100 indicates division by 100.

For example, consider 14%, which means 14 parts per 100.

Use the definition of percent: write 14 over 100.

The fraction bar indicates division.

Write the whole number 14 in decimal notation by placing a decimal

point immediately to its right and entering a zero to the right of

the decimal point.

Since the divisor 100 has two zeros, move the decimal point 2

places to the left.

Write a zero to the left of the decimal point.

We have found that 14% 0.14. This example suggests the following procedure.

0.14

.14 0

14.0 100

 14  100

14%

14

100

Writing Percents as Decimals

To write a percent as a decimal, drop the % symbol and divide the given

number by 100 by moving the decimal point 2 places to the left.

EXAMPLE (^6) TV Websites The graph below shows the percent of
market share for the top 5 network TV show websites.
a.Write the percent of
market share for the
American Idolwebsite
as a decimal.
b.Write the percent of
market share for the
Deal or No Deal
website as a decimal.
StrategyWe will drop the
% symbol and divide each
given number by 100 by
moving the decimal point 2 places to the left.
WHYRecall from Section 4.4 that to find the quotient of a decimal and 10, 100,
1,000, and so on, move the decimal point to the left the same number of places as
there are zeros in the power of 10.
Solution
a.From the graph, we see that the percent market share for the American Idol
website is 32.86%. To write this percent as a decimal, we proceed as follows.
Drop the % symbol and divide 32.86 by 100 by moving
the decimal point 2 places to the left.
Write a zero to the left of the decimal point.
32.86%, written as a decimal, is 0.3286.

 0.3286

32.86%.32 86

Self Check 6

a.Write 16.43% as a decimal.

b.Write 2.06% as a decimal.

Now TryProblems 51 and 57





American Idol (FOX) 32.86%

Dancing with the Stars (ABC) 10.42%

Survivor (CBS) 5.80%

Deal or No Deal (NBC) 4.52%

(Source: marketingcharts.com)

America’s Most Wanted (FOX) 3.49%

Top Five Network TV Show Websites

by Market Share of Visits (%)

(for week ended May 23, 2009)

Success Tip When percents that are greater than 100% are written as

fractions, the fractions are greater than 1. When percents that are less than 1%

are written as fractions, the fractions are less than 1001.