Answer:
18
Explanation:
I'm 90% sure I'm right but I could be wrong
4 × 18 = 72
6 × 18 = 108
72 + 108 = 180 degrees
Which means the opposite angle diagonal from 6x would also equal 108 degrees
Same thing for 4x, 72 degrees
72° + 72 ° + 108° + 108° = 360 degrees