Math Homework
Willy Ben Chen
4.1.pdf
Slide 1-4-1
Section 1-4
Calculating, Estimating, and
Reading Graphs
Slide 1-4-2
Calculating, Estimating, and Reading
Graphs
• Calculation
• Estimation
• Interpretation of Graphs
Slide 1-4-3
Calculation
There are many types of calculators such as four-
function, scientific, and graphing.
There are also many different models available and
you may need to refer to your owner’s manual for
assistance. Other resources for help are instructors
and students that have experience with that model.
Slide 1-4-4
Example: Calculation
Use your calculator to find the following:
a)
b)
c)
2601 4
1.5
Solution
a) 3.14159265 (approximately)
b) 51
c) 5.0625
Slide 1-4-5
Example: Estimation
A 20-ounce box of cereal sells for $3.12.
Approximate the cost per ounce.
Solution
Because it is an approximation, we can say
that the cost is about $3.00 for 20 ounces. This
works out to 3.00/20 = $0.15 per ounce.
Slide 1-4-6
Example: Circle Graph (Pie Chart)
Use the circle graph below to determine how many
of the 140 students made an A or a B.
A
15%
D
10%
C
40%
B
25%
F
10%
Letter Grades in College Algebra
Slide 1-4-7
Circle Graph (Continued)
Solution
Notice that there were 15% A’s and 25% B’s.
For 140 students this yields:
A: 0.15 x 140 = 21
B: 0.25 x 140 = 35
which is a total of 56 students.
Slide 1-4-8
Example: Bar Graph
The bar graph shows the number of cups of coffee, in
hundreds of cups, that a professor had in a given year.
0
2
4
6
8
10
2001 2002 2003 2004 2005
C u p s
(i n h
u n d re
d s)
a) Estimate the number of cups in 2004
b) What year shows the greatest decrease in cups?
Slide 1-4-9
Bar Graph (Continued)
Solution
a) The number of cups in 2004 appears to be
about 700.
b) The year 2005 looks to have the greatest
decrease at about 250 cups.
Slide 1-4-10
Example: Line Graph
The line graph shows the average class size of a first grade
class at a grade school for years 2001 though 2005.
14
18
22
26
30
34
S tu
d e n ts
p e r
c la
ss
’01 ’02 ’03 ’04 ’05
a) In which years did the average class size increase
from the previous year?
b) How much did the average size increase from 2001
to 2003?
Slide 1-4-11
Line Graph (Continued)
Solution
a) The average class size increased in years 2002,
2003, and 2004.
b) The average class size was 16 in 2001 and 28 in
2003 which would indicate an increase of
12 students per class.
