Direct & Inverse Variations

I think I remember how to do this from my college Physics class many years ago. (Any Physics pros on the forum can double-check me!!)

We need to find a constant - call it "k'

We have

D = k(S^2)

200 = k(60^2)

200 = k(3600)

k = 200 / 3600 = 1 / 18

So we have

D = (S^2) / 18

I think you can take it from here......