90.The graph provides a good approx-
imation of the number of mobile
homes (in thousands) placed in use
in the United States from 2000
through 2008.
(a)Use the given ordered pairs to
find the average rate of change
in the number of mobile homes
per year during this period.
(b)Explain how a negative slope
is interpreted in this situation.
91.The total amount spent on plasma
TVs in the United States changed
from $1590 million in 2003 to
$5705 million in 2006. Find and
interpret the average rate of change
in sales, in millions of dollars per
year. Round your answer to the
nearest hundredth. (Source:Con-
sumer Electronics Association.)
92.The total amount spent on analog
TVs in the United States changed
from $5836 million in 2003 to
$1424 million in 2006. Find and interpret the average rate of change in sales, in millions
of dollars per year. Round your answer to the nearest hundredth. (Source:Consumer Elec-
tronics Association.)
Brain Busters Use your knowledge of the slopes of parallel and perpendicular lines.
93.Show that , , , and are the vertices of a parallelo-
gram. (Hint:A parallelogram is a four-sided figure with opposite sides parallel.)
94.Is the figure with vertices at , , , and a parallelo-
gram? Is it a rectangle? (Hint:A rectangle is a parallelogram with a right angle.)
1 - 11, - 521 - 2, - 192 1 12, - 102 1 3, 4 2
1 - 13, - 92 1 - 11, - 12 1 2, - 22 1 4, 6 2
160 CHAPTER 3 Graphs, Linear Equations, and Functions
2000 2002
(2000, 281)
(2008, 79)
2004 2006 2008
Mobile Homes(in thousands)
Source: U.S. Census Bureau.
Mobile Homes Placed in Use
Year
50
0
100
150
200
250
300
EXERCISES 95 –100
FOR INDIVIDUAL OR GROUP WORK
Three points that lie on the same straight line are said to be collinear.Consider the
points , , and. Work Exercises 95 – 100 in order.
95.Find the slope of segment AB.
96.Find the slope of segment BC.
97.Find the slope of segment AC.
98.If slope of segment slope of segment slope of segment AC, then A,
B, and Care collinear. Use the results of Exercises 95 –97to show that this
statement is satisfied.
99.Use the slope formula to determine whether the points , , and
are collinear.
100.Repeat Exercise 99for the points 1 0, 6 2 , 1 4, - 52 , and 1 - 2, 12 2.
1 5, 0 2
1 1, - 22 1 3, - 12
AB= BC=
A 1 3, 1 2 B 1 6, 2 2 C 1 9, 3 2
RELATING CONCEPTS
