1. The Percent Proportion

2. Finding an unknown (x)in a proportion
“Cross” Multiply
15x =
120 x 4
15x = 480
Solve the one step equation by dividing both sides by 15
x = 32 x 4
= 32 = 15
120

3. Finding an unknown (x)in a proportion
“Cross” Multiply
20x =
90 x 7
20x = 630
Solve the one step equation by dividing both sides by 20
x = 31.5 x 7
= 31.5 = 20 90

4. Finding an unknown (x)in a proportion
“Cross” Multiply
10x =
25 x 15
10x = 375
Solve the one step equation by dividing both sides by 10
x = 37.5 25 = 10 15 x
= 37.5

5. Finding an unknown (x)in a proportion
“Cross” Multiply
2x =
6 x 15
2x = 90
Solve the one step equation by dividing both sides by 2
x = 45 6 = 2 15 x
= 45

6. What makes up a percent proportion?
Part
Whole
Percent
100 =

7. Another way to remember…is of %
100 =

8. Finding a Part

9. What number is 40% of 120? %
100 is of 40 x =
120
100
100x = 120x40
100x = 4800
x = 48

10. What number is 12% of 72? %
100 is of 12 x = 72
100
100x = 72x12
100x = 864
x = 8.64

11. Finding a percent

12. = x 9 15 100 15x = 9x100 15x = 900 x = 60 What percent of 15 is 9? %

13. 20 is what percent of 25 ? %
100 is of x 20 = 25
100
25x = 20x100
25x = 2000
x = 80

14. Finding a whole

15. 18 is 25% of what number ? %
100 is of 25 18 = x
100
25x = 18x100
25x = 1800
x = 72

16. 0.1% of what number is 4 ? %
100 is of
0.1 4 = x
100
0.1x = 4x100
0.1x = 400
x = 4000

17. 106.6 60% 8 81.8% Try These 80 is 75% of what number?
What percent of 5 is 3?
40% of 20 is what?
90 is what percent of 110?
60% 8
81.8%