Answer:
5.02
Explanation:
Formula for area= π x r^2
(π is 3.14)
Formula for diameter= 2 x r
So all you basically have to do is go backwords with the first equation
20/π=6.36
Now you have 6.36, though you need to go even further back because of the ^2
√6.36=2.51
Now we have the radius, so stick that into the diameter formula
2 x 2.51
5.02 is the diameter :)