The real answer is going to be 23.5
The answer is 6 ft, because you have the lenght of right side minus the length of left side, which is 13-7=6
If we look at the rest of the input and output, we also realize that:
output = input + 5
Thus if the input is 'n' then the output is 'n+5'
Hope that helps!
As I can tell the tables are right but it would be a function since none of the x's repeat
1.25
hope it helped and sorry if it's wrong i wish you luck