Hi there!
In order to solve for the circumference, we first need the radius or diameter. In order to find the radius, we'll use the formula for the area of a circle and work backwards.
WORK:
Area formula: A = pi x r^2
Plug in the area: 16pi = pi x r^2
Divide both sides by pi: 16 = r^2
Take the square root of each side: r = 4
Now that we know the radius is equal to 4 centimeters, we know that the diameter is equal to 8 centimeters because the diameter is equal to double the radius. Next, we'll use the formula for the circumference of a circle to solve for the circumference.
WORK:
Circumference formula: C = pi x Diameter
Plug in the diameter: C = pi x 8
Multiply: C = 8pi cm
ANSWER:
B - 8pi cm
Hope this helps!! :)
If there's anything else that I can help you with, please let me know!