1.9. Linear Pairs http://www.ck12.org
(^6) PSQand (^6) QSRare a linear pair.
m^6 PSR= 180 ◦
m^6 PSQ+m^6 QSR=m^6 PSR
m^6 PSQ+m^6 QSR= 180 ◦
Example A
What is the value of each angle?
These two angles are a linear pair, so they are supplementary, or add up to 180◦. Write an equation.
( 7 q− 46 )◦+( 3 q+ 6 )◦= 180 ◦
10 q− 40 ◦= 180 ◦
10 q= 220 ◦
q= 22 ◦
So, plug inqto get the measure of each angle.
m^6 ABD= 7 ( 22 ◦)− 46 ◦= 108 ◦ m^6 DBC= 180 ◦− 108 ◦= 72 ◦
Example B
Are^6 CDAand^6 DABa linear pair? Are they supplementary?
The two angles are not a linear pair because they do not have the same vertex. However, they are supplementary,
120 ◦+ 60 ◦= 180 ◦.