Practice C - Tequesta Trace Middle

Name ________________________________________ Date __________________ Class__________________
LESSON
1-x
1-9
Practice C
Applications of Proportions
Find the value of x in each diagram.
1. ΔACD ~ ΔABE
2. ΔQRV ~ ΔTRS
_________________________________________
________________________________________
3. Keshawn is 5 ft 6 in. tall and casts a shadow
that is one-fourth his height. At the same time,
a nearby tree casts a shadow that is twice
Keshawn’s height. Write and solve a proportion
to find the height of the tree.
_____________________________________
4. A triangle has an area of 20 in2. Every dimension
of the triangle is multiplied by a scale factor, and
the new triangle has an area of 180 in2. What
was the scale factor?
_____________________________________
5. A rectangular prism has a volume of 112 cm3.
Every dimension of the rectangular prism is
multiplied by a scale factor and the new volume
is 1.75 cm3. What was the scale factor?
_____________________________________
Original content Copyright © by Holt McDougal. Additions and changes to the original content are the responsibility of the instructor.
1-69
Holt McDougal Algebra 1
12 cm2; 48 cm2
Challenge
1. bc: 7 • 15 = 105; ad: 5 • 21 = 105
bd
2. a. Multiply each side by
ac
7.
8. They are the same.
b. Cross-Product Property;
Multiplication Property of Equality;
Identity Property of Multiplication
a
c
3.
=
b
d
1. 15
3.
Cross-Product Property;
Multiplication Property of Equality;
Identity Property of Multiplication
5.
2. $8800
3. 63,000 babies
4. 0.53 mi/min
5. C
6. G
3.
2. 6
5.5
1.375
; 44 feet
=
x
11
4. 3
8. F
5.
1
4
Review for Mastery
16 oz
1 lb
or
1 lb
16 oz
1. 15.6 ft
2. 6.125 cm
2. no; the second quality is not 1.
3. 5; 25; (5) 3 = 125
3. The two quantities are equal.
4. ratio; rate; ratio
1 12
6. Possible answer: =
2 24
⎛2⎞
⎜3⎟
⎝ ⎠
2
4 8
;
9 27
4.
2
;
3
5.
10 10 10
;
;
;
7
7
7
5. 28 pg/hr
=
3
1000
⎛ 10 ⎞
⎜ 7 ⎟ = 343
⎝ ⎠
6. The ratio of the areas is the square of the
ratio of corresponding dimensions:
1-9 APPLICATIONS OF PROPORTIONS
2
1
⎛ 1 ⎞
⎜ 20 ⎟ = 400 .
⎝
⎠
Practice A
2. 28
7. The ratio of the circumferences is equal to
the ratio of corresponding dimensions: 4.
5
4
; 15 feet
=
12
x
Challenge
4. width = 4 cm; length = 12 cm
5.
1
2
1. 7.5
1. 2.67 donuts/minute
3.
5.5
4
; 27.5 feet
=
20
x
Practice C
Problem Solving
1. 4
2. 3.2
4. The ratio of the volumes is the cube of
the ratio of the corresponding sides.
d
c
=
b
a
1.
1
4
Practice B
⎛ 1 ⎞
⎜ ab ⎟ bc
⎝ ⎠
7. D
Reading Strategies
9.
10. The ratio of the areas is the square of the
ratio in problem 5.
ad = bc
⎛ 1 ⎞
⎜ ab ⎟ ad =
⎝
⎠
1
2
1
2
1. ST ; YZ
2. 1 in.; 2 in.; 3.5 in.
6. 16 cm; 32 cm;
3. DE ; XY
4. 2 in.; 4 in.
Original content Copyright © by Holt McDougal. Additions and changes to the original content are the responsibility of the instructor.
A9
Holt McDougal Algebra 1

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