Hello!
All of these angles will add up to 360°. We can write an equation below.
90+9x+1+5x-12+8x+61=360
Now we combine like terms.
140+22x=360
We subtract 140 from both sides.
22x=220
We divide both sides by 22.
x=10
Now we plug this into the equation for angle D.
5(10)-12
50-12
38
Therefore, m∠D=38°
I hope this helps!
