17.2 Complementary and
Supplementary Angles
Common Core Standards
8. G.5 Use informal arguments to establish facts about the angle sum and
exterior angle of triangles, about the angles created when parallel lines
are cut by a transversal, and the angle-angle criterion for similarity of
triangles. For example, arrange three copies of the same triangle so that
the sum of the three angles appears to form a line, and give an argument
in terms of transversals why this is so.
WARM-UP
1) Fill in the missing
angles
e
f
94o
h
2) Find x.
x
4x
Complementary and Supplementary
Angles
Do some combinations of angles have special
names?
40o
50o
130
o
50o
NOTES
Any angles that add up to 180 degrees are called
supplementary.
Examples
What is the measure of an angle supplementary to the
given angle?
160o
700
EXAMPLES
What is the measure of an angle supplementary to the
given angle?
C
C
EXAMPLES
Are the angles supplementary?
106o
144o
740
16o
EXAMPLES
Find x.
5x
30o
94o
2x
NOTES
Any angles that add up to 90 degrees are called
complementary.
Examples
What is the measure of
angle b?
What is the measure of
angle c?
c
b
30
o
81o
EXAMPLES
What is the measure of an angle complementary to the
given angle?
27.5 o
1o
86
2
Are the angles complementary?
36
o
740
EXAMPLES
Find x.
25 o
4x
x
5x
PRACTICE
What is the measure of a
supplementary angle?
What is the measure of a
complementary angle?
o
41
C
Find x.
2x
135
3x
o
70o
FINAL QUESTION
Are the angles complementary?
32o
58o