The circumference of a circle is mc008-1.jpg feet. what is the length of the radius of this circle?

You have not provided the equation, therefore, I can only help with the concept and you can apply the steps on the numbers you have.

Circumference of a circle can be calculated using the following rule:
circumference = 2πr
where:
π is a constant = 3.14
r is the radius of the circle

Since the circumference is given, therefore, all we have to do is substitute in the equation and solve for the radius

Examples:
Assume that the circumference is 6.28 in:
circumference = 2πr
6.28 = 2 * 3.14 * r
r = 1 in

Assume that the circumference is 12.9 cm:
circumference = 2πr
12.9 = 2 * 3.14 * r
r = 2.05414 cm

Hope this helps :)