Answer:
50.5 degrees
Explanation:
Since this is a parallelogram then...
Angle U + Angle R = 180
3x+4+9x-10=180
Combine like terms
12x-6=180
Add 6 to both sides
12x=186
Divide both sides by 12
x=15.5
Now we plug 15.5 in for x to find Angle U
3(15.5)4=46.5+4=50.5
Angle U = 50.5 degrees