If the circumference of a circle is 16 what is the radius?

The equation that is used here is Circumference = 2 pi radius or C = 2 pi r

If the circumference is 16, solving for r in the equation yields: r = 16 / 2 pi

Answer is r = 8 / pi and since pi = 3.28 .... you can do the math from here.

Hope this helps.