Download Lesson 1 - Classifying Angles Examples Exercises

Name
Date
Period
Homework
Geometry & Probability
Unit B
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Lesson 1 - Classifying Angles
• An angle is formed by two rays that share a common endpoint called the vertex.
• An angle can be named in several ways. The symbol for angle is ∠.
• Angles are classified according to their measures. Two angles that have the same measure are said
to be congruent.
Acute Angle
Right Angle
Obtuse Angle
Straight Angle
less than 90°
exactly 90°
between 90° and 180°
exactly 180°
Examples
Name each angle below. Then classify the angle as acute, right, obtuse, or straight.
1.
2.
A
2
1
B
D
C
Use the vertex as the middle letter and a point
from each side, ∠ABC, ∠CBA, or use the
vertex or the number only, ∠B or ∠1.
Use the vertex or the number only, ∠D or ∠2. The
angle is less than 90˚, so it is an acute angle
The angle is 90˚, so it is a right angle.
Exercises
Name each angle below. Then classify the angle as acute, right, obtuse, or straight.
1. _________________
2. _________________
3. _________________
1. _________________
2. _________________
3. _________________
Q
M
3
H
N
O
4. AIRPORT The runways at a local airport are sketched in the figure.
Classify ∠1 and ∠2 as acute, obtuse, right, or straight.
4. ∠1 _________________
5. ∠2 _________________
1
2
page 2
G&P Unit B Lesson 1
Extra Practice
Name each angle in four ways. Then classify the angle as acute, right, obtuse, or straight.
R
1
Z
T
B
2
X
4
C
A
Y
S
1. _________________
2. _________________
3. _________________
1. _________________
2. _________________
3. _________________
1. _________________
2. _________________
3. _________________
1. _________________
2. _________________
3. _________________
1. _________________
2. _________________
3. _________________
M
H
D
E
6
F
3
J
7
G
F
P
4. _________________
5. _________________
6. _________________
4. _________________
5. _________________
6. _________________
4. _________________
5. _________________
6. _________________
4. _________________
5. _________________
6. _________________
4. _________________
5. _________________
6. _________________
Use the figure at the right to name the following.
G
F
two acute angles
J
11. _________________ 12. _________________
two straight angles
13. _________________ 14. _________________
two right angles
15. _________________ 16. _________________
two obtuse angles
17. _________________ 18. _________________
A
B
E
C
D
H