Hi Jimmy.
Starting with the surface area, let's say that
4pi(r^{2}) = j(pi) where j is a whole number between 1000 and 9999.
Then r has to be a whole number as well.
1000 ≤ 4r^{2 }≤ 9999
250 ≤ r^{2}< 2500
15 < r < 50
Now let's look at the volume and define k(pi) = (4/3) pi (r^{3}) where k
is a whole number between 1000 and 9999.
1000 ≤ (4/3)r^{3}≤ 9999
750 ≤ r^{3}< 7500
9 < r ≤ 19
Put these together and you end up with 16 ≤ r ≤ 19, but notice that
if (4/3)(r^{3}) = a whole number, then r must be divisible by three.
That means 18 is the only possibility.
(4/3)(18^{3}) = 7776.
4(18^{2}) = 1296.
Stephen La Rocque.>
