1.8. Supplementary Angles http://www.ck12.org
Set up an equation.
78 ◦+m^6 PQR= 180 ◦
m^6 PQR= 102 ◦Example B
What are the measures of two congruent, supplementary angles?
Supplementary angles add up to 180◦. Congruent angles have the same measure. Divide 180◦by 2, to find the
measure of each angle.
180 ◦÷ 2 = 90 ◦
So, two congruent, supplementary angles are right angles, or 90◦.
Example C
Name one pair of supplementary angles in the diagram below.
One example is^6 INMand^6 MNL.
Watch this video for help with the Examples above.
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/52593CK-12 Foundation: Chapter1SupplementaryAnglesB
Vocabulary
Two angles aresupplementarywhen they add up to 180◦.