Download Vocab(1). - Wiki6Math

Warm Up
Add five more straight lines to make
10.
Point
one of three undefined terms in geometry!
An exact position or location in a given plane.
Is represented by a dot and named with a capital letter.
Point A
or
Point B
Line
one of three undefined terms in geometry!
The set of points between points P and Q in a plane and
the infinite number of points that continue beyond the
points.
PQ
Q
Written as
P
Line Segment
A line with two endpoints.
Written as AB
Ray
A line that has one endpoint and continues on forever in
the opposite direction.
Circle
• The set of points on a plane at a certain distance,
or radius, from a single point, the center
Angle
Made up of 2 rays joined together at a common point
called a vertex.
The angle is
ABC
Perpendicular Line
Two lines that intersect at a right angle (90°).
Written as AB  PQ
Parallel Line
Lines in a plane that either do not share any points and
never intersect, or share all points.
Written as AB PQ
Distance along a line
The linear distance between two points on a given line.
How far apart are the points
on the line segment?
How far apart are the points
on the line segment?
Hmmm…
Degrees
The unit of measure for angles.
Acute Angle
An angle measuring less than 90° but greater than 0°.
Right Angle
An angle that measures 90°.
Obtuse Angle
An angle measuring greater than 90° but less than 180°.
Straight Angle
An angle measuring exactly 180°.
Adjacent Angles
Two angles that share a common vertex and side.
SIDE BY SIDE
Vertical Angles
Two angles directly across from each other. They share
a common vertex.
e
h
f
g
Linear Pair
Two adjacent angles that form a straight line.
1
2
Complementary Angles
Two angles that add up to 90 degrees.
30
60
1
2
Supplementary Angles
Two angles that add up to 180°.
1
20
160
2
A
B
C
Practice
(20 minutes)
*Use your vocabulary to
help you…Check your
Answers on the Board!*
Pre-image
The original figure before undergoing a transformation.
Image
The new, resulting figure after a transformation
Isometry
A transformation in which the preimage and image are
congruent.
Transformations are called RIGID
if every image is congruent to its
preimage.
Rigid transformations can also be
referred to as an ISOMETRY.
Every segment is congruent to its image.
Which of the following are rigid
transformations? (Isometry)
* Translations
(Slide your image over)
* preimage
* image
* Reflections
(Flip your image over)
* preimage
* image
* Rotations
(Turn your image
about a fixed point)
* image
* preimage
In the figure, XYZ → ABC by a
reflection. Name the image of
 X.
X
A
Z
Y
C
B
A
Parallelogram MATH is
transformed to Parallelogram
LOVE by a rotation.
What is the image of HT?
M
A
E
V
L
H
T
O
EV
Find the value of each variable,
given that the transformation is
an isometry.

6x  72
x  12
10 72
3y  2  10
3y  12
y4
6 x
3y  2
x  12, y  4
Congruent
Figures are congruent if they have the same shape, size,
lines, and angles.
Similar Triangles
Triangles are similar if they have the same shape but
have different sizes.
Corresponding angles are congruent and
corresponding sides are proportional
Trapezoids ABCD and EFGH are similar
A
ABCD ~ EFGH
B
E
F
H
D
G
C
Write the statement of proportionality
AB
BC
CD
DA



EF
FG
GH
HE
List all congruent
angles
A   E
B   F
C  G
D  H
Determine if the polygons are similar.
Justify your answer.
EX 4
7
5
4
4
5
6
6
7
NOTE: You must check for corresponding
angles to be the same and for the sides to
be proportional.