Answer:
Length = 47 in
Radius = 47/π in
Explanation:
Let 'h' be the length of the package, and 'r' be the radius of the cross section.
The length and girth combined are:

The volume of the cylindrical package is:

Rewriting the volume as a function of 'r':

The value of 'r' for which the derivate of the volume function is zero yields the maximum volume:

The length is:

The dimensions that yield the maximum volume are:
Length = 47 in
Radius = 47/π in