Hey there Javin!
The formula the we would use is. . .
[tex]d=2r[/tex]
This would mean that we would just multiply what ever is the diameter.
So, in this case, this coin has the diameter of 22, we do [tex](22*2)[/tex] and that would give us 44. (but that is not the answer quite yet).
_____________________________________________________________
The formula of a Circle is [tex]A= \pi r^2[/tex] We now know that the diameter is 22.So this would mean that the radius is half of this, which is 11.
Plug int he number's in the formula, 3.14*11^2 ≈ 379.94
Your correct answer would be . . .
[tex]\boxed{\boxed{379.94}}[/tex]
Hope this helps.
~Jurgen
