Download Lesson 1-4 Angle Measure with answers.notebook

Lesson 1­4 Angle Measure with answers.notebook
September 09, 2014
Lesson 1-4 Angle Measure
Essential Question
Questions/Main Ideas:
Ray - part of a line - has one endpoint and goes on forever
in one direction
B
A
C
named AB, AC
(name must start with the endpoint)
Questions/Main Ideas:
Opposite Rays - two rays that when put end to end form a
line
J
K
L
KJ + KL = JL
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Lesson 1­4 Angle Measure with answers.notebook
September 09, 2014
Questions/Main Ideas:
Angle
Formed by two noncollinear rays that have a common
endpoint.
X
side YX
5
vertex Y
side YZ
Symbols:
Questions/Main Ideas:
Y
XYZ
ZYX
5
Z
Note: If there is more than
one angle at a vertex, you
must name it using 3 letters.
An angle divides a plane into 3 parts
G
A
C
B
D
H
E
F
Points C and G are in the interior of the angle.
Points B, E, and H are in the exterior of the angle.
Points A, D, and F are on the angle.
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Lesson 1­4 Angle Measure with answers.notebook
September 09, 2014
G
Questions/Main Ideas:
Example 1
5
B
A
7
6
D
3
4
E
F
a.
Name all the angles that have B as a vertex.
b.
Name the sides of
c.
Write another name for
5.
6.
Questions/Main Ideas:
Degree - unit used to measure angles
there are 360 in a circle
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Lesson 1­4 Angle Measure with answers.notebook
Questions/Main Ideas:
September 09, 2014
Classifying Angles
Right Angle
m X = 90
Note: m
Acute Angle
m Y < 90
Obtuse Angle
90 < m Z < 180
X is read as "the measure of angle X"
Questions/Main Ideas: Example 2
U
V
T
S
W
Y
X
Measure each angle and classify it as right, acute, or
obtuse.
a.
TYV
b.
WYT
c.
TYU
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Lesson 1­4 Angle Measure with answers.notebook
80
90
100
90
80
70
100
110
130
70
60
120
140
50
130
40
140
30
110
120
60
50
3°
40
150
30
160
150
20
20
160
170
10
10
170
180
0
0
September 09, 2014
180
Questions/Main Ideas:
Congruent Angles - angles that have the same measure
(shown by putting arcs in the angles)
L
J
K
N
JKL≅
M
MKN
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Lesson 1­4 Angle Measure with answers.notebook
Questions/Main Ideas:
September 09, 2014
B
Example 3
G
A
H
K
C
I
J
E
D
Find m GBH and m HCI if GBH ≅ HCI,
m GBH = 2x + 5, and m HCI = 3x - 10
Questions/Main Ideas:
Angle Bisector - divides an angle into two congruent angles.
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Lesson 1­4 Angle Measure with answers.notebook
September 09, 2014
Summary
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