1. The Percent Equation

2. The Percent Equation
A percent is a ratio that compares a number to 100.
You can use the percent equation to solve percent problems.
The percent equation is related to the equation y = mx. It describes the relationship between the part (y) and the whole (x).

3. Finding the Part
You can use the percent equation to solve percent problems.
The part is dependent on the value of the whole and on the percent.
You can see this relationship using a percent bar.

4. Finding the Whole
You can use the percent equation to solve percent problems.
The whole represents 100%.

5. Finding the Percent
You can use the percent equation to solve percent problems.
The percent is the ratio that describes the proportional relationship between the part and the whole.

6. Examples
Write whether each question or equation is looking for the part, the percent, or the whole. Circle the portion of each statement that led you to the answer.
a. 4 is what percent of 6? _____________
b. 65 = 30/100 · x _____________
c. What is 79% of 126? _____________
d. 11 = m · _____________
e. y = 0.48 · _____________
f. 4% of what number is 12? _____________
g. 190 is 10% of what number? _____________

7. Solve each percent problem.
Examples
Solve each percent problem.
11 is what percent of 50?
25 is 4% of what number?
What is 40% of 60?

8. Examples Which of the following is/are true? a. 7 is 50% of 14.
b. 28 is 14% of 200.
c. 6 is 40% of 14.
d. 40% of 35 is 14.

9. Examples
A hairdresser is paid $7.50 per hour. After a year, he is to receive an 8% raise. Is the information in the letter correct? Explain.

10. Examples
Suppose your friend has given you a gift certificate for a haircut. After the haircut, you want to leave an appropriate tip for the hairdresser. The receptionist says you should leave exactly $3 if you want to tip 20% of the price of the hair cut. What was the price of the haircut?

11. Focus Question
How do percents and the percent equation help describe things in the real world?
Percents are a common language that help to communicate and compare information. The percent equation helps to describe proportional relationships in the real world. You can use the percent equation to find or verify numbers in the real world.

12. HW:
Percent Equation Worksheet