UNIT 4: PERCENTS

1
UNIT 4 PERCENTS

• Indicates number of hundredths in a whole
• Decimal fraction can be expressed as a percent by
  moving decimal point two places to right and
  inserting percent symbol
• Express 0.375 as a percent

• Move decimal point two places to right
• Insert percent symbol

0.375 37.5 Ans
2
FRACTIONS TO PERCENTS

• To express a common fraction as a percent, first
  divide to get the decimal fraction. Then convert
  to a percent
• Express each of the following as percents

625 Ans
3
PERCENTS TO FRACTIONS

• Decimal Fractions
• To express percent as decimal fraction
• Drop percent symbol
• Move decimal point two places to left
• Express 25.4 as a decimal

• Drop percent sign
• Move decimal point left two places

25.4 .254 Ans
4
PERCENTS TO FRACTIONS

• Common Fractions
• To express percents as common fractions
• First convert percent to decimal fraction
• Express 64.5 as a common fraction

5
PERCENT TERMS DEFINED

• All simple percent problems have three parts
• Base
• Rate
• Percentage
• Rate is percent ()
• Base represents whole or a quantity equal to 100
• Word of generally relates to base
• Percentage is part or quantity of percent of base

6
PERCENT TERMS DEFINED

• Word is generally relates to percentage
• Identify base, rate, and percentage
• What percent of 64 is 8?
• Problem is asking for rate (percent)
• 64 represents whole and is identified by word
  of, so it is the base
• 8 represents part and is identified by word is,
  so it is the percentage

7
FINDING THE PERCENTAGE

• Formula for finding percentage given rate and
  base
• Percentage Rate Base
• If rate is less than 100, percentage is less
  than base
• If rate is greater than 100, percentage is
  greater than base

8
FINDING THE PERCENTAGE

• What is 7.5 of 120?
• Rate 7.5 (7.5 is .075 as a decimal)
• Base 120
• Problem is asking for percentage

Percent Rate Base
.075 120
9 Ans
9
FINDING THE RATE

• Formula for finding rate (percent) given base and
  percentage is
• What percent of 76 is 49.4?

10
FINDING THE RATE

• Base 76
• Percentage 49.4
• Problem is asking for rate

Ans
11
FINDING THE BASE

• Formula for finding base given rate and
  percentage
• 17.5 is 12.5 of what number?

12
FINDING THE BASE

• Percentage 17.5
• Rate 12.5 (.125 as a decimal)
• Problem is asking for base

140 Ans
13
PRACTICE PROBLEMS
1. Express each of the following as a percent.
2. Express each of the following as a decimal
fraction. a. 1.46 b.
100 c. 0.05
3. Express each of the following as a common
fraction or mixed number. a. 14.4
b. 2.5 c. 138
14
PRACTICE PROBLEMS

• 4. Round to two decimal places whenever necessary
  in each of the following
• What is 12 of 150?
• What percent of 234 is 86?
• 14.5 is 45 of what number?
• What is 8 ¾ of 640?
• What percent of 50 is 75?
• What is 125 of 75?
• 200 is 37 ½ of what number?
• What percent of 1375 is 350?
• 135 is 150 of what number?