Question 824966
Without quoting formula references,

{{{(1/3)13^2*16=2*pi*r^2*k}}}, where r is the radius of the cylinder and k is the length of the cylinder.  They both are variables and unknown because your description did not give any way to specify either.  You can pick a value for one of them and find the corresponding value of the other of them.



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Note to student:
You need to give an effort.  Your question and description is incomplete and you have TWO variables and enough information for ONE equation.  Identify the formulas needed and make the equation.  Solve for r, the radius of your expected cylinder, which still involves an unknown height, which in the equation shown, is k.