Miss Dawn's

1
Miss Dawn's
6th Grade Math
Working with
Angles
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Angle
An angle is formed by two rays that have the same
endpoint.
H
ray
The point where two rays meet is called the vertex
K
ray
A
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Protractor
A protractor is a tool for measuring angles.
90 degrees
H
B
A
It is divided into units called degrees.
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Measuring

• To measure an angle

• place the center mark of the protractor

• on the vertex of the angle

• and the zero mark on a side of the angle.

J
vertex
R
centermark
zero mark
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Right Angle
A Right Angle is an angle with a measure of 90
degrees.

90
L
B
R
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Acute
An Acute angle is an angle with a measure less
than 90 degrees.
50
T
V
B
This acute angle measures 50 degrees.
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Obtuse
An Obtuse angle is an angle with a measure
greater than 90 degrees and less than 180 degrees.

150
V
M
N
This obtuse angle measures 150 degrees.
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Bisector
A bisector divides an angle into two congruent
parts.
A Right angle has two equal parts measuring 45
degrees.
R
U
S
T
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Your Turn!
Is this angle properly lined up on the protractor?
NO!
Why not?
The vertex is not lined up on the center of the
protractor.
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Angles?
What type of angle is this?

• Right angle

• Acute angle

• Obtuse angle

Acute!
Correct. This angle measures 75 degrees, less
than 90 degrees.
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Angles?
What type of angle is this?

• Right angle

• Acute angle

• Obtuse angle

Right angle
Correct. This angle measures 90 degrees, it is a
right angle.
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Angles?
What type of angle is this?

• Right angle

• Acute angle

• Obtuse angle

Obtuse
Correct. This angle measures 120 degrees.
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Bisected?
Is this angle bisected?
YES!
The bisector enters at 60 degrees, cutting the
120 degree angle in half.
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Grades
What were the grades from the last section?
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Stay Tuned!
Our next lesson will be how to properly bisect an
angle!