Answer:
<MON = 102°
Explanation:
Alternative Interior Angles so both of those angle equal to each other.
(12x + 30) = (9x + 48)
Get x to one side by subtracting.
12x - 9x + 30 = 48
3x + 30 = 48
Subtract 30 to both side to get x by itself.
3x = 18
Divide 3 to both side to solve for x.
x = 6
Plug x = 6 into <MON = (9x + 48)
9*6 + 48 = 54 + 48 = 102°