Transcript 7-7 Finding the Percent of a Number

Finding the Percent of a Number
LESSON 7-7
Course 1
Additional Examples
Use a proportion to find 60% of 45.
Let n represent the number you want to find.
n
60
=
45
100
100  n = 60  45
100n = 2,700
n = 27
60% of 45 is 27.
part
whole
Write the cross products.
Multiply.
Divide each side by 100.
Finding the Percent of a Number
LESSON 7-7
Course 1
Additional Examples
Find 88% of 250.
88% = 0.88
Write 88% as a decimal.
0.88  250 = 220
Multiply.
So, 88% of 250 is 220.
Finding the Percent of a Number
LESSON 7-7
Course 1
Additional Examples
Use mental math to find 75% of 84.
What you think
3 3
75% is equivalent to 4 ; 4
 84 = 63. 75% of 84 is 63.
Why it works
75
75% = 100
= 3
3
4

4
3
84
84 = 4  1
252
=
4
= 63
Write 75% as a fraction in simplest form.
3
84
Multiply 84 by 4 . Rewrite 84 as 1 .
Simplify.
Divide.