Percentage of a Number
12-3
Think
45% 50%
50%
1(^12)
180
Think
162 is close to the estimate of 180.
First estimate.
75% of $24
^34 $24$18
1
$6
45%
or
162
198
percentage
Think
78%75%
and 4 and 24
are compatible
numbers.
Think
$18.72 is close
to the estimate
of $18.
Find: 45% of 360 p.
First estimate the percentage (or part) of a number, using benchmark
percents. Benchmark percents are commonly known and frequently used
percents such as 10%, 25%, and 50% and their common fractions.
45% of 360 50% of 360
^12 360 180
45% of 360 180
Then use a formula to find the percentage, p, of a number.
rate (r)base (b)percentage (p) rbp
Rename the percent (rate) as a decimalor as a fraction. Then solve.
As a Decimal As a Fraction
r b p r b p
45% of 360p 45% of 360p
0.45 360 p 1
4
0
5
0
360 p
18
0.45 162 p 2
9
0
36
1
^0
p
1
0.45 162 p
So 45% of 360162.
Study this example.
Find: 78% of $24.
Then solve.
78% of $24p
0.78$24p
$18.72p
78% of $24 $18 So 78% of $24$18.72.
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