Title: Lesson 6-5
Author: Kathy Halverson
Last saved by: MHE
Company: Halverson Household

Lesson 6-4

For Examples 3-5	Use the Percent Proportion
Use a proportion to solve.
a. What number is 25% of 484?
The percent is 25, and the whole is 484.  Let n represent the part.
            = 	Write the percent proportion.
     n ⋅ 100 	   = 484 ⋅ 25	Find the cross products.
            100n = 12,100 	Multiply 484 and 25.
(100n) ÷ 100 = 12,100 ÷ 100	Divide each side by 100.
                  n = 121	Divide 12,100 by 100.
25% of 484 is 121.
b. 16 is 80% of what number?
The percent is 80% and the part is 16.  Let n represent the whole.

            	= 	Write the percent proportion.
   16 ⋅ 100 	= n ⋅ 80	Find the cross products.
       1,600 	= 80n	Multiply 16 and 100.
  1,600 ÷ 80 = (80n) ÷ 80	Divide each side by 80.
             20	= n	Divide 1,600 by 80.

16 is 80% of 20.

c.  4 is what percent of 5?
4 is being compared to 5.  So, 4 is the part and 5 is the whole.

Words		Four is what percent of 5?
Variable		Let n represent the percent.
Proportion	part/whole		=   

             	= 	Write the percent proportion.
      4 ⋅ 100	= 5 ⋅ n	Find the cross products.
           400	= 5n	Multiply 4 and 100.
         	= 	Divide each side by 5.
             80	= n	

4 is 80% of 5.

d.  11 is what percent of 5?
11 is being compared to 5.  So, 11 is the part and 5 is the whole.  You need to find the percent. 

            	= 	Write the percent proportion.
   11 ⋅ 100 	= 5 ⋅ n	Find the cross products.
        1100	= 5n	Simplify.
        	= 	Divide each side by 5.
          220 	= n	

11 is 220% of 5.

e. [Real World] SCHOOL	In a sixth grade class, 18 of the 30 students are female.  What percent of the students in the class are female?

Compare the number of females, 18, to the total number of students in the class, 30.  The part is 18 and the whole is 30.  Let n represent the percent.

            	= 	
    18 ⋅ 100	= 30 ⋅ n	Find the cross products.
         1800	= 30n	Multiply.
        	=	Divide each side by 30.
            60 	= n	
60% of the students in the class are female.