# Math Help - Problem

1. ## Problem

what is the answer 4 this question?
If the circumference of a coin is 7.7 what is the radius? what should I do frist

2. Circumference of a circle is given by pie multiplied by the diameter.

in this case

pie times diameter = 7.7

diameter = 7.7 / pie

$C = 2\pi r \: \: \therefore r = \frac{C}{2\pi} = \frac{7.7}{2\pi}$