The answer is 28.2457
The formula to find the circumference is
2 πr. And the area formula is πr^2
To get the radius, you have to do
18.84/π
Which will result in 5.9969582557 as the diameter.
Then you do
5.9969582557/2
To get the radius of 2.99847912785.
Then you square it
2.99847912785^2
To get
8.990877080152097
Multiply that by Pi to get 28.2457