3.9: Conversion of Decimals, Fractions, and Percent
Suppose you're taking the written test for your driver's license and you get
Percent Problems
A percent is a ratio whose denominator is 100. Before we can use percents to solve problems, let's review how to convert percents to decimals and fractions and vice versa.
To convert a decimal to a percent, multiply the decimal by 100.
Example A
Convert 0.3786 to a percent.
To convert a percentage to a decimal, divide the percentage by 100.
Example B
Convert 98.6% into a decimal.
When converting fractions to percents, we can substitute
Example C
Express
We start by representing the unknown as
Guided Practice
Express 75% as a reduced fraction.
Solution:
75% means
Practice
Sample explanations for some of the practice exercises below are available by viewing the following video. Note that there is not always a match between the number of the practice exercise in the video and the number of the practice exercise listed in the following exercise set. However, the practice exercise is the same in both. CK12 Basic Algebra: Percent Problems (14:15)
Express the following decimals as percents.
 0.011
 0.001
 0.91
 1.75
 20
Express the following fractions as a percent (round to two decimal places when necessary).

16 
524 
67 
117 
1397
Express the following percentages as reduced fractions.
 11%
 65%
 16%
 12.5%
 87.5%
Image Attributions
Here you'll learn how to change a decimal to a percent, a percent to a decimal, a fraction to a percent, and a percent to a fraction.