Vocabulary Flash Cards
angle of rotation
Chapter 4 (p. 190)
center of rotation
Chapter 4 (p. 190)
component form
Chapter 4 (p. 174)
congruence transformation
Chapter 4 (p. 201)
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center of dilation
Chapter 4 (p. 208)
center of symmetry
Chapter 4 (p. 193)
composition of
transformations
Chapter 4 (p. 176)
congruent figures
Chapter 4 (p. 200)
Big Ideas Math Geometry
Vocabulary Flash Cards
The fixed point in a dilation
The angle that is formed by rays drawn from the
center of rotation to a point and its image
P′
P
C
R′
R
Q
Q′
R
40°
center of dilation
Q
Q′
R′
angle of
rotation
center of rotation
The center of rotation in a figure that has rotational
symmetry
P
The fixed point in a rotation
R′
The parallelogram has
rotational symmetry. The
center is the intersection

of the diagonals. A 180
rotation about the center
maps the parallelogram
onto itself.
R
40°
Q
Q′
center of rotation
The combination of two or more transformations to
form a single transformation
A glide reflection is an example of a composition
of transformations.
angle of
rotation
P
A form of a vector that combines the horizontal
and vertical components
Q
2 units up vertical
P
component
4 units right
horizontal component
The component form of
Geometric figures that have the same size and
shape
B
A
E
C
F

PQ is 4, 2 .
A transformation that preserves length and angle
measure
Translations, reflections, and rotations are three
types of congruence transformations.
D
ABC  DEF
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Big Ideas Math Geometry
Vocabulary Flash Cards
dilation
Chapter 4 (p. 208)
glide reflection
Chapter 4 (p. 184)
image
line of reflection
Chapter 4 (p. 182)
All rights reserved.
Chapter 4 (p. 208)
horizontal component
Chapter 4 (p. 174)
initial point
Chapter 4 (p. 174)
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enlargement
Chapter 4 (p. 174)
line symmetry
Chapter 4 (p. 185)
Big Ideas Math Geometry
Vocabulary Flash Cards
A dilation in which the scale factor is greater than
1
A transformation in which a figure is enlarged or
reduced with respect to a fixed point
A dilation with a scale factor of 2 is an
enlargement.
P′
P
C
Q
Q′
R
center of dilation
R′
Scale factor of dilation is
The horizontal change from the starting point of a
vector to the ending point
CP
.
CP
A transformation involving a translation followed
by a reflection
Q
Q′
P′
P
Q″
4 units right
P″
horizontal component
Q
P
k
The starting point of a vector
A figure that results from the transformation of a
geometric figure
K
B
6
y
C′
B′
4
A
J

Point J is the initial point of JK .
A figure in the plane has line symmetry when the
figure can be mapped onto itself by a reflection in
a line.
C
D
D′
A′
2
6
4
x
ABC D is the image of ABCD after a translation.
A line that acts as a mirror for a reflection
4
y
A
B
2
m
C
C′
B′
6
x
A′

Two lines of symmetry
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ABC  is the image of
in the line m.
ABC after a reflection
Big Ideas Math Geometry
Vocabulary Flash Cards
line of symmetry
Chapter 4 (p. 185)
reduction
Chapter 4 (p. 208)
rigid motion
Chapter 4 (p. 176)
rotational symmetry
Chapter 4 (p. 193)
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preimage
Chapter 4 (p. 174)
reflection
Chapter 4 (p. 182)
rotation
Chapter 4 (p. 190)
scale factor
Chapter 4 (p. 208)
Big Ideas Math Geometry
Vocabulary Flash Cards
The original figure before a transformation
B
6
y
A line of reflection that maps a figure onto itself
C
C′
B′
4
A
D
D′
A′
2
4
x
6
ABCD is the preimage and ABC D is the image
after a translation.
A transformation that uses a line like a mirror to
reflect a figure
4
A dilation in which the scale factor is greater than
0 and less than 1
y
A
A dilation with a scale factor of
B
2
m
C
x
6
A′
ABC  is the image of
in the line m.
1
is a reduction.
2
B′
C′

Two lines of symmetry
ABC after a reflection
A transformation in which a figure is turned about
a fixed point
A transformation that preserves length and angle
measure
R
R′
Translations, reflections, and rotations are three
types of rigid motions.
40°
Q
Q′
angle of
rotation
center of
rotation
P
The ratio of the lengths of the corresponding sides
of the image and the preimage of a dilation
P′
P
C
Q
Q′
R
center of dilation
R′
Scale factor of dilation is
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CP
.
CP
A figure has rotational symmetry when the figure

can be mapped onto itself by a rotation of 180 or
less about the center of the figure.
The parallelogram has rotational
symmetry. The center is the
intersection of the diagonals.

A 180 rotation about the
center maps the parallelogram
onto itself.
Big Ideas Math Geometry
Vocabulary Flash Cards
similar figures
similarity transformation
Chapter 4 (p. 216)
terminal point
Chapter 4 (p. 216)
transformation
Chapter 4 (p. 174)
translation
Chapter 4 (p. 174)
Chapter 4 (p. 174)
vector
Chapter 4 (p. 174)
vertical component
Chapter 4 (p. 174)
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Big Ideas Math Geometry
Vocabulary Flash Cards
A dilation or a composition of rigid motions and
dilations
6
A(−4, 1)
B(−2, 2)
y
B″(6, 6)
A″(2, 4)
4
2
Geometric figures that have the same shape, but
not necessarily the same size
y
Q
P
2
B′(3, 3) C″(6, 4)
A′(1, 2) C′(3, 2)
−4
−2
W
−2
4
C(−2, 1)
−4
X
Y
2
4
6
ABC is the image of ABC after a
6
x
Z
8 x
S
R
Trapezoid PQRS is similar to trapezoid WXYZ.
similarity transformation.
A function that moves or changes a figure in some
way to produce a new figure
The ending point of a vector
K
Four basic transformations are translations,
reflections, rotations, and dilations.
J

Point K is the terminal point of JK .
A quantity that has both direction and magnitude,
and is represented in the coordinate plane by an
arrow drawn from one point to another
A transformation that moves every point of a
figure the same distance in the same direction
y
K
A′
A
3
B′
C
C′
J

JK with initial point J and terminal point K.
2
4
B
6
8 x
ABC is the image of ABC after a translation.
The vertical change from the starting point of a
vector to the ending point
P
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Q
2 units up vertical
component
Big Ideas Math Geometry