6th Grade Math Textbook, Progress

Angle Pairs

10-3

Pairs of angles can be classified according to their degree measures or sides.

ABCand 
FEDare

complementary angles.

37°
53°90°

GHIand 
LKJare

supplementary angles.

57°
123°180°

Adjacent angles are two angles that

are in the same plane and share a

common side and a common vertex,

but have no interior points in common.

Vertical angles are two congruent angles formed by

intersecting lines. Their sides are pairs of opposite rays.


AEDand 
BEFare vertical angles.

So are 
DEBand 
AEF.

Study these examples.

Find the value of x.

 1 and 
 2 are adjacent angles. 
 3 and 
 4 are a linear pair.

m
 3 
m
 4 180°

43°
x90°

x47°

x
75°180°

x105°

3 x45°

x15°

Complementary angles are two angles

whose measures have a sum of 90°.

Each angle is said to be the

complement of the other.

Supplementary angles are two angles

whose measures have a sum of 180°.

Each angle is said to be the

supplement of the other.

When the noncommon sides of two

adjacent angles are opposite rays, the

angles form a linear pair. The angles

of a linear pair are supplementary.

A

C

B

37 °

F

D

53 °

E I

G

57 °

H J

L

K

123 °

1 2

M N P

O

43

A B C

D

A F

D B

E

x

43 ° x^75 °

3 x^45 °

common side

AED
 
BEF


AEF
 
BED

2.2

8206-2_334-335 10/7/07 11:50 AM Page 334