1. Find each number. Round to the nearest tenth if necessary.
Do Now
Find each number. Round to the nearest tenth if necessary.
What percent of 60 is 15?
9 is 45% of what number?
What number is 12% of 72

2. Objective: Solve problems by using the percent equations
Chapter 8 Lesson 2
Algebra: The Percent Equation
Objective: Solve problems by using the percent equations

3. The graph shows three main elements that make up most of the human body.
1. Suppose a person weighs 120 pounds. Use the percent proportion to find the number of pounds of oxygen, carbon, and hydrogen.
Carbon
18%
Other 7%
78 lb.
21.6 lb
12 lb
Oxygen
65%
Hydrogen
10%
2. Express the percent of each element as a decimal.
.65
.18 .1
78 lb.
21.6 lb
12 lb
3. Multiply each decimal by Round your results.
Compare the answers to exercises 1 and 3.
They are the same

4. Recall in lesson 7-8 Percent proportion Is Of X 100 = Part Base
You used the percent proportion to find the missing part, percent, or base. You can also use an equation.

5. Today we are doing the same as we did in lesson 7-8 except
instead of writing the problem as a ratio and then solving it, today we are writing it as an equation and then solving it.

6. IS means equals OF means X
Recall
IS means
equals
OF means X

7. Types of percent problems
Example
Proportion
Equation
Find the Part
(IS)
What number is 50% of 6?
N = 50
N = 0.5 x 6
Find the Percent
3 is what percent of 6? n
6 = 100
3 = n x 6
Find the Base
(OF)
3 is 50% of what number?
N = 100
3 = 0.5 x n

8. Lets try some together!! N = 0.12 x 350 42 What number is 12 % of 350?
Write an equation for each problem. Then solve. Round to the nearest tenth if necessary.
What number is 12 % of 350?
N = 0.12 x 350 42

9. Write an equation for each problem. Then solve
Write an equation for each problem. Then solve. Round to the nearest tenth if necessary.
21 is what percent of 40?
21 = n x 40
52.5%

10. Write an equation for each problem. Then solve
Write an equation for each problem. Then solve. Round to the nearest tenth if necessary.
13 is 26% of what number?
13 = 0.26 x n 50

11. Your turn!!!
Write an equation for each problem. Then solve. Round to the nearest tenth if necessary.
What number is 65% of 98?
N = 0.65 x 98
N = 63.7

12. Your turn!!!
Write an equation for each problem. Then solve. Round to the nearest tenth if necessary.
Find 53% of 470.
N = 0.53 x 470
N = 249.1

13. Your turn!!!
Write an equation for each problem. Then solve. Round to the nearest tenth if necessary.
9 is what percent of 45?
9 = n x 45
N = 20%

14. Your turn!!!
Write an equation for each problem. Then solve. Round to the nearest tenth if necessary.
26 is what percent of 96?
26 = N x 96
N = 27.1%

15. Your turn!!!
Write an equation for each problem. Then solve. Round to the nearest tenth if necessary.
84 is 75% of what number?
84 = 0.75 x n
N = 112