6th Grade Math Textbook, Progress

Update your skills. See page 17.

Measure and Draw Angles

10-1

An angle is a plane figure formed by two rays with

a common endpoint. Each ray is a side of the angle,

and the endpoint is the vertex of the angle.

sides: EC, EB vertex:E

angle: 
CEBor 
BECor 
E

Plane XYZcontains 
CEB.

An angle separates a plane into three sets of points:

the angle itself, the points in the interior of the angle,

and the points in the exterior of the angle.

Point Zis in the interiorof 
CEB.

Points Xand Yare in the exteriorof 
CEB.

Angles are measured in degrees (°).

A protractor is used to measure or draw an angle.

To measure 
XYZ:


 Using the inner scale, place

the center mark of the protractor

on the vertex of the angle,

Y, with YX pointing to 0
.


 Read the measure of the

angle where YZ crosses

the protractor.

To draw an angle of 140
: Mark Pat the 140
point on the protractor.


 Draw a base ray, MN. Use

the outer scale.


 Place the center mark of

the protractor on Mwith

MN pointing to 0
.


 Mark Pat 140
.


 Draw MP.














measure

of 
XYZ

Z

interior

exterior

E

C B

X Y

Y

X

7080 90 Z

60

50

40

30

20

10

0

(^100110)
(^120130)
140
150
160
170
180
(^908070)
(^6050)
40
30
20
10
0
110100
120
130
140
150
160
170
180
M
N
P
708090
60
50
40
30
20
10
0
(^100110)
(^120130)
140
150
160
170
180
(^908070)
(^6050)
40
30
20
10
0
110100
120
130
140
150
160
170
180
m
XYZ 55

measure
of
NMP
m
NMP 140

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