Percentsby Mrs. Fredericks

• Use the percent proportion• =

• Use the percent equation• part = percent • whole

Using the percent proportion

=

Find the percentWhat percent of 15 is 9?

Let n represent the percent =

9 • 100 = 15n900 = 15n

15 15

n = 60 so it is 60%

Find the partWhat number is 40% of 120?

Let p represent the part =

40 • 120 = 100p4800 = 100p

100 100

p = 48

Find the whole18 is 25% of what number?Let w represent the whole

= 18 • 100 = 25 w

1800 = 25 w 25 25

w = 72

Using the percent equation

part = percent • whole

Find the percent21 is what percent of 40?

Let n represent the percent21 = n • 40

21 = 40n 40 40

n = 0.525

YOU MUST CHANGE THE DECIMIAL TO % FORMSo we must rewrite it as 52.5%

Find the partWhat number is 12% of 150?

Let p represent the part

YOU MUST USE THE DECIMAL FORM OF THE %

p = 0.12 • 150

p = 18

Find the whole13 is 26% of what number?Let w represent the whole

YOU MUST USE THE DECIMAL FORM OF THE %

13 = 0.26 • w13 = 0.26w

0.26 0.26w = 50

Try this problem, use either method.

3 is 12% of what number?

Proportion Equation = part = percent • whole

= 3 = 0.12 • w

12w = 300 3 = 0.12w12 12 0.12 0.12 w = 25 w = 25

Let’s try one more. Use the other method this time.

What is 72% of 50?

Proportion Equation = part = percent • whole

= p = 0.72 • 50

100p = 3600 p = 36100 100 p = 36