Page 191 - Math Course 1 (Book 1)

Percent Proportion

Find the Part

Examples
What percent of 8 is 12?

Twelve is being compared to 8. So, 12 is the part
and 8 is the whole. Let n represent the percent. What number is 8.8% of 20?

The percent is 8.8, and the whole is 20. Let n
represent the part.
12 n Write the percent proportion.
=
8 100
12 • 100 = 8 • n Find the cross products. n 8.8 Write the percent proportion.
=
20 100
1200 = 8n Simplify
1200 8n n • 100 = 20 • 8.8 Find the cross products.
= Divide each side by 8.
8 8
100n =176 Simplify
150 = n Simplify.
n = 1.76 Mentally divide each side by
100.
Answer 150% of 8 is 12.

Answer 8.8% of 20 is 1.76.

Find the Whole Apply the Percent Proportion

Examples TENNIS

From the years 1999 through 2005, Serena Williams
won the U.S. Open Tennis Championships two
Seventy is 28% of what number? times and Wimbledon two times. What percent of
both tournaments combined during those years
The percent is 28%, and the part is 70. Let n was Serena Williams the women’s champion?
represent the whole. Round to the nearest tenth.

70 28
= Write the percent proportion.
n 100

70 • 100 = n • 28 Find the cross products.
7000 = 28n Simplify
7000 28n
= Divide each side by 28.
28 28

250 = n Simplify. Compare the number of Serena Williams’ wins, 4,
to the total number of tournaments played, 14. The
part is 4 and the whole is 14. Let n represent the
percent.
Answer 70 is 28% of 250.

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