Formula of circle:
C= 2πr
The radius is half of the diameter, so divide 9 by 2
18/2=9
Then plug in 9 as the radius in the formula.
C= 2π(9)
Using you calculator multiply 2 by the symbol "π" and 9
Exact Form is 18π
Decimal Form is 56.54866776...
Ur answer is going to have to be A the rest don’t make sense