



 
Hi John, We had a similar question a while ago about a roll of paper. Have a look at my response to this question. The radius of the roll is
In your example L = 3000 × 12 = 36000 inches, t = 0.005 inches and r = 6/2 = 3 inches. Thus
Thus the diameter of the roll is 2 × 8.14 = 16.28 inches. Penny  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 