7th Grade Math

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Applying Percents

PART A B CDE F

Multi-Part

Lesson 3

GLE 0706.2.4

Use ratios, rates and

percents to solve single-

and multi-step problems

in various contexts.

SPI 0706.2.7 Use ratios

and proportions to solve

problems.

346 Percent

Main Idea

Find the percent of

increase or decrease.

Vocabulary

percent of change

percent of increase

percent of decrease

Percent of Change

FOOTBALL The table shows about how many people

attended the home games of a high school football team each year.

Attendance of Home Games

Year Total Attendance(thousands)

2007 16.6

2008 16.4

2009 16.9

2010 17.4

2011 17.6

1. How much did the attendance increase from 2009 to 2010?


2. Write the ratio __amount of increase
   attendance in 2009
   . Then write the ratio as
   a percent. Round to the nearest hundredth.


3. How much did the attendance increase from 2008 to 2009?


4. Write the ratio __amount of increase
   attendance in 2008
   . Then write the ratio as
   a percent. Round to the nearest hundredth.


5. MAKE A CONJECTURE Why are the amounts of increase the same but
   the percents different?

When you subtracted the original amount from the final amount, you

found the amount of change. When you compared the change to the

original amount in a ratio, you found the percent of change.

Percent of Change

Words A percent of change is a ratio that compares the change in

quantity to the original amount.

Equation percent of change =

amount of change

__

orginal amount

=

final amount - original amount

___

original amount

When the percent of change is positive, then it is called a percent of

increase. When the percent of change is negative, then it is called a

percent of decrease.

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