Download 14.3 Complementary and Supplementary Angles

14.3 Complementary and
Supplementary Angles
Common Core Standards
7.G.2. Draw (freehand, with ruler and protractor, and with technology)
geometric shapes with given conditions. Focus on constructing
triangles from three measures of angles or sides, noticing when the
conditions determine a unique triangle, more than one triangle, or no
triangle.
7.G.4. Know the formulas for the area and circumference of a circle and
use them to solve problems; give an informal derivation of the
relationship between the circumference and area of a circle to write and
solve simple equations for an unknown angle in a figure.
7.G.5. Use facts about supplementary, complementary, vertical, and
adjacent angles in a multi-step problem to write and solve simple
equations for an unknown angle in a figure.
WARM-UP
1) Fill in the missing
angles
e
f
93o
2) If m∠KLM = 74o , find
the measure of an
adjacent angle along a
straight line to ∠KLM.
h
3) If m∠KLM = 74o, find
the measure of an angle
vertical to ∠KLM.
Complementary and Supplementary
Angles
Do some combinations of angles have special
names?
40o
50o
130
o
50o
NOTES
Any two angles that add up to 180 degrees are called
supplementary. Supplementary angles along a straight
line are called a linear pair.
Examples
What is the measure of an angle supplementary to the
given angle?
160o
700
EXAMPLES
Are the angles a linear pair?
106o
144o
740
16o
NOTES
We can use equations to solve for missing information
in a picture.
Examples
Find x.
5x
30o
94o
2x
NOTES
Any two 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
Are the angles complementary?
36
o
740
EXAMPLES
Find the missing angle, x.
25 o
72o
2x
5x
EXAMPLES
o
If m∠ABC = 34 , find the
measure of an angle
supplementary to ∠ABC.
o
If m∠GHJ = 47 , find the
measure of an angle
complementary to∠GHJ.
PRACTICE
What is the measure of a
supplementary angle?
What is the measure of a
complementary angle?
o
o
41
41
Find x.
2x
135
3x
o
70o
PRACTICE
o
If m∠ABC = 46o and m∠CBX = 125 , are the two angles
a linear pair?
PRACTICE
Find x.
4x
x
FINAL QUESTION
Find x.
8x
x