Name_____________________________________ Class____________________________ Date________________
Lesson 3-7
Percent of Change
Lesson Objectives
1
Find percent of change
NAEP 2005 Strand: Number Properties and Operations
Topic: Ratios and Proportional Reasoning
Topics:
2
Find percent error
Local Standards: ____________________________________
Vocabulary.
expressed as a
.
All rights reserved.
Percent of change is the ratio
Percent of increase is
Percent of
is the percent of change found when a value decreases from its
original amount.
The greatest possible error in a measurement is
Percent
is the ratio of the greatest possible error and the measurement.
Examples.
1 Finding Percent of Change The price of a skirt decreased from $32.95 to
© Pearson Education, Inc., publishing as Pearson Prentice Hall.
$28.95. Find the percent of decrease.
amount of change
percent of decrease original amount
32.95 Subtract to find the amount of change.
Substitute the original amount.
32.95
32.95
Simplify the numerator.
or
%
The price of the skirt decreased by about
40
Algebra 1 Lesson 3-7
Write as a decimal and then as a percent.
.
Daily Notetaking Guide
L1
Name_____________________________________ Class____________________________ Date ________________
2 Finding the Greatest Possible Error You read the bathroom scale as 122 lb.
What is your greatest possible error?
The scale is read to the nearest
one half of 1 lb, or
lb, so the greatest possible error is
lb.
Quick Check.
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1. a. Find the percent of change if the price of a CD increases from $12.99 to
$13.99. Round to the nearest percent.
b. Find the percent of change if the CD is on sale, and its price decreases from
$13.99 to $12.99. Round to the nearest percent.
© Pearson Education, Inc., publishing as Pearson Prentice Hall.
2. You measure a picture for the yearbook and record its height as 9 cm. What is
your greatest possible error?
L1
Daily Notetaking Guide
Algebra 1 Lesson 3-7
41