Percent Proportions and Percent Bars
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Transcript of Percent Proportions and Percent Bars
Finding Percents of numbers
Using the Is over Of technique in conjunction with drawing
percent bars
What do you think is the answer??
• Find 25% of 20
• Let’s draw a picture.
100%
? 25%
20
Can you solve this as a proportion? • Find 25% of 20
• What would the proportion look like?
100%
? 25%
20
10025
20x
X = 5
We can do this Mathematically by using a special
proportion...just find the following...
The Percent – it is the easiest to find.Just look for the % sign!
The “Of” number - it is always just behind the word of.
The “Is” number - it may or may not be near the “is” word. If you find the other two then what is left is the “is”!
Finding is, of or a Percent
Find the missing number by drawing a bar and using the proportion.
a) 15% of 900 is what?
100
%=
of
isUse the proportion…
15%
100900
?
10015
900x
x = 135
Finding is, of or a Percent
Find the missing number by drawing a bar and using
the proportion.
b) What % of 84 is 63?
100
%=
of
is
x%
10084
63100%
8463
X = 75%
Finding is, of or a Percent
c) 35% of what # is 7?
100
%=
of
is
Find the missing number by drawing a bar
and using the proportion.
35%
100?
7
10035
x7
X = 20
Finding is, of or a Percent
Find the missing number by drawing a bar and using the proportion.
d) 2.5% of 120 is what?
100
%=
of
is
2.5%
100120
?
1005.2
120x
x = 3
Finding is, of or a Percent
Find the missing number by drawing a bar and using the proportion.
60% of 600 is what number?
100
%=
of
is
60%100600
x10060
600x
x = 360
Homework: P. 322 #2-26 evens
You MUST show the proportion and the work you do to get the answer.