It looks like you need to flip the second figure to line it up with the first figure. So the bottom right side has a ratio of 27:9 or 3:1
In other words the left figure is 3 times bigger than the right figure. So my answers are:
1) 18, because it is 3 times bigger than 6.
2) 5 1/3 or 5.33, because 16/3 is 5 1/3.
3) 8, because 24 divided 3 is 8.
Unfortunately, I did not get 8.25 as my answer for 2). Hopefully that is fine.