### Chapter 6: Percent

```Chapter 6
Percent
6.3 Using the Percent Proportion and Identifying
the Components in a Percent Problem
Objectives
1. Learn the percent proportion.
2. Solve for an unknown value in a percent
proportion.
3. Identify the percent.
4. Identify the whole.
5. Identify the part.
Slide 6.3- 2
The percent proportion can be used to solve
problems.
Slide 6.3- 3
Parallel
Example 1
Using the Percent Proportion
Use the percent proportion and solve for the
unknown value. Let x represent the unknown.
a. part = 20, percent = 80; find the whole.
p a rt

w h o le
p a rt
20
w h o le
x
p e rce n t
100

80
p e rce n t
100
100
Find the cross products.
20
x
Show that the cross
products are equivalent.

80
100
x • 80
20 • 100
80  x  20 100
80  x  2000
x  25
Slide 6.3- 4
Parallel
Example 1
Using the Percent Proportion
Use the percent proportion and solve for the
unknown value. Let x represent the unknown.
b. part = 12, whole = 40; find the percent.
p a rt

w h o le
p a rt
12
w h o le
40
3
10
p e rce n t
100


x
p e rce n t
100
100
x
Write the fraction in lowest terms.
100
10  x  3 100
Find the cross products.
10  x  300
Divide both sides by 10.
x  30
The percent is written as 30%.
Slide 6.3- 5
Parallel
Example 1
Using the Percent Proportion
Use the percent proportion and solve for the
unknown value. Let x represent the unknown.
c. whole = 120, percent = 90; find the part.
p a rt

p e rce n t
w h o le
100
p a rt
x
w h o le
120
90
p e rce n t
100
100

x

120
9
10
Write the fraction in lowest terms.
10  x  9 120
Find the cross products.
10  x  1080
Divide both sides by 10.
x  108
The part is 108.
Slide 6.3- 6
Percent Problems
All percent problems involve a
comparison between a part of
something and the whole.
Percent
The percent is the ratio of a part to a
whole, with 100 as the denominator. In
a problem, the percent appears with
the word percent or with the symbol
“%” after it.
Slide 6.3- 7
Parallel
Example 2
Finding the Percent in Percent
Problems
Find the percent in the following.
a. 20% of the 740 customers were children.
Percent
b. \$90 is what 40 percent of what number?
Percent
c. What percent of 320 is 272?
Percent (unknown)
Slide 6.3- 8
Whole
The whole is the entire quantity.
In a percent problem, the whole
often appears after the word of.
Slide 6.3- 9
Parallel
Example 3
Finding the Whole in Percent Problems
Find the whole in the following.
a. 14% of 600 cars were convertibles.
Whole
b. \$200 is 30 percent of what number?
Whole
c. 70% of 8220 is what number?
Whole
Slide 6.3- 10
Part
The part is the portion being
compared with the whole.
Note: If you have trouble identifying the part, find the
percent and the whole first. The remaining number is
the part.
Slide 6.3- 11
Parallel
Example 4
Finding the Part in Percent Problems
Identify the part. Then set up the percent
proportion. (Do not solve.)
a.
60% of 450 animals is 270 animals.
Percent;
with % sign
Whole
Part
Whole
Part
270
450

60
100
Percent
Always 100
Slide 6.3- 12
Parallel
Example 4
Finding the Part in Percent Problems
Identify the part. Then set up the percent
proportion. (Do not solve.)
b.
\$240 is 10% of what number?
Part
Percent
Part
Whole
Whole
(unknown)
240
u n kn o w n

10
100
Percent
Always 100
Slide 6.3- 13
Parallel
Example 4
Finding the Part in Percent Problems
Identify the part. Then set up the percent
proportion. (Do not solve.)
c.
35% of 600 is what number?
Percent
Whole
Part
Whole
Part
(unknown)
unknow n
600

35
100
Percent
Always 100