Notes for Section 1-4

1
Notes for Section 1-4
Measuring Segments and Angles
2
To measure a segment, we can use a ruler and
measure the distance between the two ____________.
OR
We can think of the segment as part of a
___________ line.
A
B
C
D
E
F
G
H
I
- 4
- 3
- 2
- 1
0
1
2
3
4
3
Look at segment AE
How can we determine the length of segment AE?
The coordinate of A is _______
The coordinate of E is _______


A
B
C
D
E
F
G
H
I
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- 3
- 2
- 1
0
1
2
3
4
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Congruent Segments
Two segments with the same ____, denoted __
Can you determine some congruent segments from
the number line below?
A
B
C
D
E
F
G
H
I
- 4
- 3
- 2
- 1
0
1
2
3
4
5
Practice 1-4 4 - 7
6
An important postulate.
If three points A, B, and C are _______ and B is
between A and C, then ________________.
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Practice 1-4 1 3, 9 - 11
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Midpoint
A point that divides a segment into two _________
segments.
A midpoint _____ the segment.
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Lets look at the following example.
Z is the midpoint of segment XY, and XY 27.
Find XZ.
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Practice 1-4 21 - 22
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Angle
A
Formed by two _____ with the same endpoint,
denoted ___
1
B
C
There are four ways to name this angle.
The endpoint is called the _____ of the angle.
__________________________
12
One way to express the measure of an angle is in
_________.
65
B
We would write this as
______________
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Angle Measuring Activity
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Acute Angle
An angle with measurement between ____ and ____
degrees.
15
Right Angle
An angle with measurement of _____ degrees.
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Obtuse Angle
An angle with measurement between ____ and ___
degrees.
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Straight Angle
An angle with measurement of ____ degrees.
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An important postulate
If point B is in the ________ of ?AOC,
then _________________________
A
B
O
C
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Congruent Angles
Angles with the same ________.
For example
If ____________,
Then ____________
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Practice 1-4 8, 12 - 20