Do you remember that the circumference of every circle is
Circumference = (pi) times (the circle's diameter) ?
Well, before we get to work on the problem, let's take this big hairy
gigantic complicated formula, and divide each side by (pi):
the circle's diameter = (circumference) / (pi) .
In the problem, you're given the circumference, you're told to use 3.14 for (pi),
and you're asked to find the diameter.
I'm pretty sure that you can handle it from this point.