Find the value of the circumference of a circle with the given diameter.

3.21 ft.

C =

A = 1.61 pi

B = 3.21 pi

C = 6.42 pi

C = 2πr, and 2r = D (diameter). So, you can also use this equation: C = D π

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