Answer:
110º
Step-by-step explanation:
The two given angles are co-interior angles, and add up to 180º.
So, set up an equation.
3x+4 + 5x = 180
8x = 176
x = 22
Now, angle D is also cointerior to angle C, meaning THEY add up to 180 as well.
D + 3x+4 = 180
sub x=22
D + 3(22)+4 = 180
D = 180 - 70
D = 110
