A cylindrical tin can holding 2gal. has its height equal to the diameter of its base. Another cylindrical tin can with the same capacity has its heights equal to twice the diameter of its base. Find the ratio of the amount of tin required for making the two cans with covers. (1gal = 231 cu. in.)

The Correct Answer: 0.95245

This is what I did, in order for me to get the ratio this is my working equation:

...and then the answer I got is. I don't which part am I wrong in solving the ratio..r = 0.8818895

I am glad to be corrected..Thanks for the help in advance..