NOTES 3.7 – PERCENTS
CHANGING A PERCENT TO A FRACTION
Step 1 - Place the percent over ______.
100
Step 2 - ________
REDUCE the fraction to a proper fraction or
mixed numeral in lowest terms.
Example 1 - Change 20% to a fraction
1
20

20% =
5
100
Example 2 - Change 125% to a fraction
125  1 1
125% =
100
4
CHANGING A FRACTION TO A PERCENT
Step 1 - Change the ___________
DECIMAL
FRACTION to a __________.
(Divide the numerator by the denominator)
Step 2 - Move the decimal point ____
2 places to the
_______.
RIGHT
7
Example 3 - Change12 to a percent.
7
58.3
0.583 = __________%
12 = __________
CHANGING A DECIMAL TO A PERCENT
Step 1 - Move the decimal point _____
2 places to the
_________.
RIGHT
Example 4 - Change 0.815 to a percent
0.815 = _______%
81.5
CHANGING A PERCENT TO A DECIMAL
Step 1 - Move the decimal point ____
2 places to the
_______.
LEFT
(If there is no decimal point, it goes at the right of the
last number in the percent)
Example 5 - Change 315% to a decimal
315% = ________
3.15
SOLVING SIMPLE PERCENT PROBLEMS
EVERY percent problem has an ___,
IS an ____,
OF and a
percent in it. Since percent means “PER HUNDRED”
we can solve every percent problem using the ratio
IS
%

OF
100
Example 6 – What is 30% of 50.
x
50

30
100
100 x  30(50)
100 x  1500
100 x
1500

100
100
x  15
YOUR TURN:
1.) 10 is what percent of 18?
10
18
18 x
18 x
18 x
18
x

x
100
 10(100)
 1000
1000

18
 55.56%
2.) 5 is 20% of what number?
5
x
20 x
20 x
20 x
20
x

20
100
 5(100)
 500
500

20
 25
3.) Find 75% of 25.
x
25
100 x
100 x
100 x
100
x

75
100
 75(25)
 1875
1875

100
 18.75
4.) 9 is 45% of what number?
9
x
45 x
45 x
45 x
45
x

45
100
 9(100)
 900
900

45
 20
Homework: p. 174 #7-45 odd