7.3.2 finding the percent (of a number)
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Transcript of 7.3.2 finding the percent (of a number)
Lesson 7.3, For use with pages 354-358
1. 4963 = 21
x2. 36
60 =x
55
Solve the proportion.
Lesson 7.3, For use with pages 354-358
ANSWER 27 ANSWER 33
1. 4963 = 21
x2. 36
60 =x
55
Solve the proportion.
Finding the Percent (of a Number)
Essential Questions
Where are different situations percents are used in real life?
As a consumer, why is it important for you to know about percents?
Today we will be looking at how to find the percent of a fraction or ratio.
For example – 4 out of 5 is ____%
Again – some problems you may be able to do in your head, while others will require the use of a proportion.
Can you do these mentally?
½ is what percent?1/5 is what percent?
¼ is ____% ¾ is _______%
1/10 is _____% 7/10 is _______%15/100 is _____% 96/100 is _____%
50%20%
25 75
10 70
15 96
Continue Mental Math 12/24 is ______%
36/48 is ______%
49 / 50 is _____%
40 / 50 is ______%
60 / 50 is ______%
50
75
98
80
120
Using a proportion to find the percent
Proportion set up will not change, but the number you are looking for will.
part %
total 100
Which part will you be looking for in the proportion?
19 is ____% of 95
Set it up using a proportion
1995
= x
100
95x 19( 100)=
95x 1,900=95 95
x = 20%
18 is x% of 54
1854
= x
100
54x 18( 100)=
54x 1,800=54 54
x = 33 1/3%
_____% of 25 is 18.75
18.7525
= x
100
25x 18.75( 100)=
25x 1,875=25 25
x = 75%
GUIDED PRACTICE for Example 1
Use a percent proportion.
1. 63 is what percent of 75 ?
6375
= x
100
75x 63( 100)=
75x 63,000=75 75
x = 840
16 out of 20 people prefer to use a debit card instead of writing a check. What percent prefers using a debit card?
What % still prefers to use a check?
1620
= x
100
20x 16( 100)=
20x 1,600=20 20
x = 80%
During basketball practice, Lisa attempted 35 free throws, but made only 28 of them. What percent attempted did she make?
Is she a good free-throw shooter?The average in the NBA is 76%.
2835
= x
100
35x 28( 100)=
35x 2,800=35 35
x = 80%
Last baseball season, Austin hit 48 home runs. So far this season, he has hit 30 home runs. The number of H-Runs hit this season is what percent of the number of H-Runs hit last season?
3048
= x
100
48x 30( 100)=
48x 3,000=48 48
x = 62.5%
Homework
Worksheet 61-62 Page 61: Do column B Page 62: All
You MUST show a PROPORTION for EVERY problem.