Percents by Mrs. Fredericks
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Transcript of Percents by Mrs. Fredericks
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