Not sure why such an old question is showing up on my feed...
Anyway, let

and

. Then we want to find the exact value of

.
Use the angle difference identity:

and right away we find

. By the Pythagorean theorem, we also find

. (Actually, this could potentially be negative, but let's assume all angles are in the first quadrant for convenience.)
Meanwhile, if

, then (by Pythagorean theorem)

, so

. And from this,

.
So,
Answer:
D. 720cm squared is the answer
The answer is 105 kilometers
You take 17.5/2.5 and get 7 and then you thanks the 7*15 and you get 105 kilometers