1. Angles
Naming
Angles
Web

2. We label the angle with three upper case letters.
Naming Angles
An angle is made of two rays.
We label the angle with three upper case letters.
Naming the Angle
Y is called the Vertex
 XYZ
 ZYX X
 Y
Exercise 9.1 (page 313) Y Z
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3. Use a single letter to name the angle.
Naming Angles
Use a single letter to name the angle. B A
Exercise 9.1 (page 313) B C
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4. Use a single letter to name the angle.
Naming Angles
Use a single letter to name the angle. Q Q P
Exercise 9.1 (page 313) R
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5. Use a single letter to name the angle.
Naming Angles
Use a single letter to name the angle. G E
Exercise 9.1 (page 313) G F
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6. Use three letters to name the angle.
Naming Angles
Use three letters to name the angle.
LNM L
Exercise 9.1 (page 313) N M
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7. Use three letters to name the angle.
Naming Angles
Use three letters to name the angle. S
RST R
Exercise 9.1 (page 313) T
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8. Use three letters to name the angle.
Naming Angles
Use three letters to name the angle.
EGF E
Exercise 9.1 (page 313) G F
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9. Naming Angles There are several ways to name this angle.
1) Use the vertex and a point from each side. S
SRT or
TRS
side
The vertex letter is always in the middle.
2) Use the vertex only. 1 R T
side
vertex R
If there is only one angle at a vertex, then the angle can be named with that vertex.
3) Use a number. 1

10. Angles DEF FED E 2 Definition of Angle
An angle is a figure formed by two noncollinear rays that have a common endpoint.
Symbols:
DEF E D F 2
FED E 2

11. Angles 1) Name the angle in four ways. ABC CBA B 1
2) Identify the vertex and sides of this angle.
vertex:
Point B
sides:
BA and BC