Grade 4 - Progress in Mathematics

Measuring Angles

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40

30

20

10

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(^130140)
150
160
170
180
(^90807060)
(^5040)
30
20
10
0
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130120
140
150
160
170
180 B C
A
Yo u can measure angles
in degrees (
) using a protractor.
Measure an angle by measuring
the distance between its sides.
Acute Angle

• measures less
  than 90
  
  Straight Angle


• measures 180
  

D

F

E

LKJ

Obtuse Angle

• measures more
  than 90
  , but less
  than 180°

G

H

I

Right Angle

• forms a square
  corner


• measures 90
  

B

A

C

Use a protractor to tell whether each angle

is right, acute, obtuse, or straight.

12. 
    
    
    
    13. 
        
        
        
        14. ZYX
        
        
        
        
    
    
    
    


13. B 16. 17. 18.

A C

H

G

I

K

J

L

E

F

D

S R

T

V

W

U

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