The quotient of two fraction is the multiplication between the first and the inverse of the second:

So, in your case, you have

So, the question now is: which is larger, 7/10 or 3/5? To answer this question, transform the second fraction so that it will have denominator 10 as well:

So, now it is clear that

If the angle =91 on the top then x=91 on the bottom is the same
As you know, to get the inverse of any expression, we start off by switching the variables about and then solving for "y",
Without doing the math, you can can see that the 100ft marker is about 1/3rd of the bottom(combining the triangle and the rectangle) This floor is practically(if not exactly) the same length of each vertical side of the building.
"100 x 3" is 300, So I am pretty sure the answer is 308.
Good luck!
-RxL