Transcript Chapter 8 Lesson 4 Percent of Change - Mrs. Wendt

Do Now
Write each proportion and answer.
1. 54% of the 1,250 kids at Park Ave. have
some computer restrictions at home.
Determine what part of the population
that is.
2. 74% of 12 year olds use IM. Predict how
many of the 2,480 middle school kids
that is.
Chapter 8
Lesson 4
Percent of Change
Objective: Find the percent of
increase or decrease
Percent Change
Is a ratio that compares the change in
quantity to the original amount.
amount of change
Percent of change =
original amount
Percent Increase
The original quantity is increased
(New amount – original amount)
amount
of
change
Percent of change =
original amount
Percent Decreased
The original quantity is decreased.
(Original amount – new amount)
amount
of
decrease
Percent of change =
original amount
Find the percent of change in tree height from one year to
year 10. Round to the nearest whole percent if necessary.
Percent of increase
Percent of change =
amount of change
original amount
9.6 - 4 = 5.6
9.6 ft
5.6
4
1.4
4 ft
140%
The percent of increase in the tree
height is 140%
Find the percent of change if the original price of a stock
was $75 and the new price is $60. Round to the nearest
whole percent if necessary.
Percent of Decrease
Percent of change =
amount of decrease
original amount
75 – 60 = $15
15
75
0.2
20%
Stock
Original
New
Price
$75
$60
Find each percent of change. Round to the nearest whole
percent if necessary. State whether the percent of change
is an increase or decrease.
Original: 10
New: 13
Increase
13 -10 = 3
3
10
30%
Find each percent of change. Round to the nearest whole
percent if necessary. State whether the percent of change
is an increase or decrease.
Original: 20
New: 15
decrease
20 - 15
5
20
25%
Find each percent of change. Round to the nearest whole
percent if necessary. State whether the percent of change
is an increase or decrease.
Original: 30
New: 24
decrease
30 – 24 = 6
6
30
20%
Find each percent of change. Round to the nearest whole
percent if necessary. State whether the percent of change
is an increase or decrease.
Original: $75.80
New: $94.70
Increase
$94.70 – 75.80 = $18.90
18.90
75.80
.249340 =
25%
Find each percent of change. Round to the nearest whole
percent if necessary. State whether the percent of change
is an increase or decrease.
Original: $126
New: $150
Increase
150 – 126 = 24
24
126
.1904 = 19%
Find each percent of change. Round to the nearest whole
percent if necessary. State whether the percent of change
is an increase or decrease.
Original: 1.6
New: 0.95
decrease
1.6 – 9.95 = .65
.65
1.6
0.40625 = 41%
Find each percent of change. Round to the nearest whole
percent if necessary. State whether the percent of change
is an increase or decrease.
Original: 624
New: 702
Increase
702 – 624 = 78
78
624
0.125 = 13%
Do numbers 11-21 odd on page
352 in your textbook
Homework
Page 352 numbers 12 – 22
even.