Name ___________________________
Class Period ____
Date __________________
ALGEBRA 1
Lesson 3-7 “ Percent of Change”
Objective I: Percent of Change
LEQ:
_______________________________________________________________________
Eligible Content:
M11.A.1.1
Represent and/or use numbers in equivalent form.
M11.D.3.1
Describe and/or determine change.
Do Now Exercises
Directions:
Write an equation for each problem, then solve the equation for the variable.
1.
What is 20% of 45?
2.
3.
18 is 90% of what number?
8 is what percent of 20 ?
Vocabulary
Percent of Change – is the ___________ of the ____________________ to the __________________
expressed as a ___________________.
Percent of Increase – is when the value __________________________________________________.
Percent of Decrease – is when the value __________________________________________________.
Key Concept #1
Finding Percent of Change
Percent of Change =
.
.
=
.
.
Examples
Directions:
Find each percent of change, describe the percent of change as an increase or decrease.
1.
30 cm to
2.
$140 to
100 cm
$ 100
3.
In 1980, Texas has 27 U.S. Representatives in Congress. That number increased to 30 in the year
2000. What was the percent of change?
Key Concept #2
Finding the Greatest Possible Error
Greatest Possible Error – in a measurement ______________________________________________.
Directions:
Find the greatest possible error for each situation.
4.
A stone’s mass was measured to the nearest 0.1g, what is the greatest possible error for this
measure?
5.
A photo frame is measured to have a width of 29 cm, what is the greatest possible error for this
measure?
Key Concept #3
Finding Percent of Error
Percent of Error – is a ______ of the _________________________ and the _____________________.
Directions:
Find the percent of error for each situation.
6.
The measure of the diameter of a music CD is 12.1 cm. Find the percent of error for this
measurement.
7.
The length of a table is measured to be 168 in. Find the percent of error for this measurement.
Summary:
How can a percent be written as a fraction?
__________________________________________________________________________________
Assignment: ______________________________________________________________________