Name
_
Date
_
..-Practice B
~
For use with pages 764 -772
..
.
rse variation,
Tell whether the equation represents direct VariatIOn,
mve
or neither.
2. xy
=-5
3. Y =x - 4
4. •x =y-
5. xy
= 14
~=
6. x
7. 2x+y=8
8.
=:;9
9. 4x - 4y = 0
1.
y= -llx
-8
3y
13
, y
11) Graph the inverse variation equation: xy =-6
..­
......
X
.
Gl
en
-.­
,
Gl
. the .Inverse
Tell whether the table represents inverse variation. If so, write
variation equation.
31.
33.
2
4
6
8
10
x
-5
-4
I
2
y
10
II
21
31
41
51
y
-4
-5
20
10
2
y
.E
II
32.
x
x
> N
-
'<t
34.
10
23
25
28
50
x
-10
-9
-6
-5
160
-4
368
400
448
800
y
-1.8
-2
-3
-3.6
-4.5
35. Catalog Orders A clothing company allows customers to place orders on the
Internet or by phone. The orders must be entered into the computer inventory
system. The number of orders n entered per person into the system varies inversely
with the number p of people working. The company estimates that 10 people
working during a shift can get 960 orders entered.
a. Write an inverse variation equation that relates nand p.
I
II
a-.
II
A.
f')
II
~
c:i
;>.-,
b. Find tbe pressure of a gas with a volume of 250 cubic inches.
I
II
~
II
"<
.t
N
!'Ii
N
N
N
I
II
c. Find the number of orders entered per person during a shift if 8 people
are working.
a. Write the inverse vaIiation equation that relates P and V.
00
-
b. Find the number of orders entered per person during a shift if 20 people
are working.
36. Volume and Pressure The volume V of a gas at a constant temperature varies
inversely with the pressure P. When the volwne is 125 cubic inches, the pressure
is 20 pounds per cubic inch.
A.
I
11
A.
II
N
II
A.
r-"
II
~
...en
A.
f')
I
II
~
...
N
-
N
I
II
~
M
N
LESSON 3.8
Practice B
Name
----------
Date - - - - - - - - -
Solve the formula for the indicated variable. 5
1. Fahrenheit to Celsius
Solve for F: C = - (F - 32)
9
2.
Perimeter ofa Parallelogram Solve for b: P
3. Perimeter ofa Triangle
4.
=
Solve for c: P
2b + 2s
=
a+b+c
Area ofa Rhombus
5. Area ofa Trapezoid
Solve for h: V = nr2 h
6.
Volume ofa Right Circular Cylinder
7.
Lateral Surface Area ofa Right Circular Cylinder
8.
Volume ofa Right Circular Cone
Solve for h: S = 2nrh
n 2 rh
Solve for h : V = - ­
3
Solve the formula for the indicated variable. Then use the given information to find the value of the
variable. Include units of measure in the answer.
9. Area ofa Parallelogram
Solve for h: A = bh
Find h when,A
=
81 cm2 and b = 9 em.
10. Celsius to Fahrenheit
9
Solve for C: F=- C + 32
5
Find C when F
=
77°F.
Basketball A regulation size basketball has a volume of 455.9 cubic inches. Use this information to
answer the following questions. Approximate your answers to the nearest tenth.
4
11. The formula for the volume ofa sphere is V= 3 nr3 . What is the radius of the basketball?
12. What is the diameter of the basketball?
13. The formula for the circumference of the basketball is C = 2nr. If the circumference of a basketball is
29 inches, is it a regulation size basketball?
Q"'
N
V-J
N
~
N
Vl
o
...
~
(j
Answer Key
Lesson 12.1
Practice Level B
1. direct v31iation 2. inverse variation 3. neither 4. inverse variation 5. inverse variation \
6. direct variation 7. neither 8. inverse variation 9. direct variation
i '~ I \
~~,IJ,
11. '
1
-,: -!,Ir
-;II
19.y
14
= -;-; 7
20.y
27 27
= -;-; 2
21.y
J
-3
I
3
= 7; -2
22.y
-II
II
= -x-; -2
-i£
23.y
144
= 7; 72
24.y
72
= -;-; 36
Ii"
-28,
3.6 '
,-2~
-~0itJ41t""'08~ ,118 S8:..y~,..._.J.~"'!Y.iZ1 p;; 1 I
x
x
X
20
18
9600
32. yes; y = 33. no 34. yes; y = 35. a. n = - - b. 480 orders
~55
3'tat'1 -:;z
2 31.no
x
x
p
x
- 2500
p b. 10 lb/'lll. 3
c. l200 orders 36. a. V -
~