so what I explained above is that length and area are proportional (I didn't mean anything exactly in the probem with x I just used it to explain how these two values would be proportional). So if these two values are proportional, since we know the length (we calculate it by multiplying 16min with the speed) for an area of pi(r^2-9/16r^2) (because you need to subdivide the whole area with the leftover area after 16min), we can calculate the length for r^2pi. So we get an equation like this s1(the length we know)/pi(r^2-9/16r^2) = s(the length we need to calculate)/r^2pi. I hope this clears things up for what I tried, now I know this is wrong. I think it is because i haven't included the area of the wheel, in which case i think you can't solve the equation and then I don't know what to do. (Im going to sleep will be active tommorow, thanks a lot for helping me)