How do you find the length of the circle if you know that the radius is 6 inches?

If you are referring to the diameter(the distance across the circle or the length of the longest line segment that is passing through the center of the circle), then the answer will be 12 in, since that the diameter is twice the length of the radius. But if you are talking about the circunference, you could use the formula C=2pi(r) or C=pi(d). Thus the answer will be 37.68 in. Please be more specific next time you ask...=)