1. Braking Down Proportions and Percents (6-6)
By: Travis, Denise, and Morgan

2. You can solve a percent problem by writing and solving a proportion.
(A model can help you write a proportion)

3. 0% part 65% n 100% 245 whole 65 = n : Write a proportion 100 245
part
65% n
100%
245
whole
65 = n : Write a proportion
65(245) = 100n : Write cross products
65(245) = 100n : Divide each side by 100
= n
65% of 245 is

4. Finding a percent N = 52: Write a proportion 100 60
60n = 100(52) : Write cross products
60n = 100(52) :Divide each side by 60
N = 86.6 repeating : Simplify
=86.7: Round
52 is approximately 86.7% of 60 0% n% 52
part
100% 60
whole

5. Sometimes you know the percent that a part represents, and you want to find the whole amount.
(You can also write as a proportion)

6. Finding a Whole Amount 46 = 207 : Write a proportion 100 n
46n = 100(207) : Write cross products
46n = 100(207) : Divide each side by 46
N = 450 : Simplify
207 is 46% of 450 0%
46%
207
part
100%
whole n

7. Key concepts on percents and Proportions
Finding the percent
What percent of 40 is 6?
N =
100% 40
Finding the part
What number is 15% of 40?
15 = n
Finding the whole
6 is 15% of what number?
15 = 6 n

8. Story Problem
Population In 1950, the population of Alaska was about 128,535. That was about 20.5% of the population of Alaska in the year About how may people lived in Alaska in the year 2000?
20.5 = 128,535 : Write a proportion n
20.5n = 100(128,535): Write cross products
20.5n = 100(128,535) : Divide each side by 20.5
The answer you should get is: 627,000 people

9. Test your Knowledge Finding part of a whole: Finding a Percent:
53% of 70 is
Answer: 37.1
Finding a Percent:
% of 25 is 13
Answer: 52
Finding the Whole Amount
3. 8 is 25% of
Answer: 32

10. Any Questions???