Well, this could be a "hecto" but in practice it's not really used. If you want to use it, you would speak of "hectometers".
if your question would be 1000 times larger, then it would be "kilo" and this one is actually widely used.
I dont get what the question is do you need to solve it or?
If your only solving for the perimeter, then the answer is 18yd.
