Basic Mathematics for College Students

576 Chapter 6 Percent

A circle graphis a way of presenting data for

comparison. The pie-shaped pieces of the graph

show the relative sizes of each category.

The 100 tick marks equally spaced around the

circle serve as a visual aid when constructing a

circle graph.

To solve percent application problems, we often

have to rewrite the factsof the problem in

percent sentence form before we can translate

to an equation.

(Source: O’Reilly Radar)

Male

Female 46%

54%

Facebook Users Worldwide

195 Million

To make the calculations easier, write the mixed number as the

improper fraction.

Write as.

To solve the proportion, find the cross products

and set them equal.

To simplify the left side, do the multiplication:

8.2  100 820.

To isolate xon the right side, divide both sides

of the equation by. Then remove the

common factor of from the numerator and

denominator.

On the left side, the fraction bar indicates

division.

On the left side, write 820 as a fraction. Use

the rule for dividing fractions: Multiply by the

reciprocal of.

Multiply the numerators.

Multiply the denominators.

Divide 2,460 by 100 by moving the understood

decimal point in 2,460 two places to the left.

Thus, 8.2 is 33 13 %of 24.6.

24.6x

2,460

100

x

1003

820

1



3

100

x

820 

100

3

x

1003

1003

820

100

3



x

100

3

1

100

3

1

820 x

100

3

8.2 100 x

100

3

33 31 1003

8.2

x



100

3

100

1003

33 13

Method 1:To find the unknown amount write and then solve a percent

equation.

is of

x  46%  195 Translate.

Now, solve the percent equation.

Write 46% as a decimal: 46% 0.46.

Do the multiplication. The answer is in millions.

In April of 2009, there were approximately 89.7 million male users of

Facebook worldwide.

x89.7

x0.46 195

What number 46% 195 million?

    

FACEBOOK As of April 2009, Facebook

had approximately 195 million users

worldwide. Use the information in the

circle graph to the right to find how many

of them were male.

The circle graph shows that 46% of the

195 million users of Facebook were male.