Question

Angle C and Angle D are supplementary angles. If the measure of Angle D is nine less than twice the measure of Angle C, find the measure of Angle D.

PLEASE HELP!!! I have no idea where to even start!

Answer 1

"Angle D is nine less than twice the measure of Angle C"

D = 2C - 9

and we know C+D = 180 , so .....

Answer 2

D= 117
C= 63