Thanks for the response, but how do you figure the radial value = 8.35 when the problem states that it is the diameter. I divided by 2 (a half) to get the radius. From there I would still be stuck in millimeters. I was thinking about then going over to volume and converting it into millimeters cubed, then dividing it by pi and (4.175 mm)^2. I'd then be left will millimeters of which I could covert back into feet. Does this work or am I making it way to complicated?