[sammyg2]

Of course it can, but the diameter may be an irrational number.

Just solve backwards. A= pi x R x R
Come up with a rational number for area, just make up a simple easy number like 3.
3= pi x R x R
Divide both sides by pi.

3/pi = r x r

diameter = approx. (.995/r) x 2

I think .........