CHAPTER 2
SECTION 3
COMPLEMENTARY AND SUPPLEMENTARY ANGLES:
GOAL: FIND MEASURES OF COMPLEMENTARY AND SUPPLEMENTARY ANGLES
Two angles are complementary angles if the sum of their measure is 90°
Two angles are supplementary angles if the sum of their measures is 180°
1
2
Angles 1 and 2 are supplementary.
3
4
Angles 3 and 4 are complementary.
Determine whether the angles are complementary, supplementary or neither.
1.
2.
64°
138°
26°
42°
43°
3.
46°
4.
155°
32°
Measures of compliments and supplements:
1.
A and
B are complements. If m
A = 28° find m
B.
2.
C and
D are supplements. If m
C = 118° find m
D.
3.
E and
F are supplements. If m
E = 35° find m
F.
Two angles are adjacent angles if they share a common vertex and side, but have no
common interior points.
Common side
1
●
2
Common vertex
1 and
2 are adjacent angles.
Determine if the numbered angles are adjacent or nonadjacent.
1.
2.
2
1
3
3.
5
6
4
Theorem 2.1
Words:
CONGRUENT COMPLEMENTS THEOREM
If two angles are complementary to the same
angle, then they are congruent.
Symbols: If m
then
1+m
1
2
1
2 = 90° and m
3.
3
2+m
3 = 90°
Theorem 2.2
Words:
CONGRUENT SUPPLEMENTS THEOREM
if two angles are supplementary to the same
angle, then they are congruent.
Symbols: If m
then
4+m
4
5 = 180° and m
6.
5
4
6
5+m
6 = 180°,
HOMEWORK
PAGE 70-71
{1-32}