What is the circumference of a circle with a radius of 8?

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Answer 1 · 2016-06-19T10:50:08

#16pi#

This is about the very definition of #pi#. That magical number is the ratio between the circumference and the diameter, i.e.

#pi=C/d#

Now, remember that the diameter is twice the radius,

#pi=C/(2r)#

And solve for #C#:

#2rpi=C#

Thus, if the radius is #8#, the circumference will be #2*8*pi=16pi#