How could I figure out this math problem? ?

Question

Hey, could you help me out a bit? I have a math problem, I know how to do but I'm not sure.

Here it is =): Circle has diameter 21 feet. Circumference is about N feet. (Hint: Pi is approx. 3.14)

So..I need the answer. And I need to know how to figure it out. Please explain it thoroughly.

Okay thanks everyone! =)

Answer 1

The formula for Circumference is 2r * pi (where r is the radius)

Diameter = 2*r

Based on the information in the problem, Diameter = 21 = 2r.

Plug this information into the circumference formula:

N = 21(pi)