Answer :

C= 2πr, and 2r = D (diameter). So, you can also use this equation: C =Dπ
Since we know the diameter, and we know the value of 
π, we can easily calculate the value of circumference. 
C = D
π
C = 3.21
π 
This means that the correct answer is B. 3.21 pi

Answer:

the answer is 3.21 pi

Step-by-step explanation:

hope it helps :)

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