I assume, that this pen is rectangular.
Look, that 48 = 24 * 2 = 12 * 2 * 2 = 3 * 2 * 2 * 2 * 2
And know choose these numbers and multiply!
First dimension: 3*2 x 2*2*2 = 6 x 8
Second: 3 x 2*2*2*2 = 3 x 16
Third: 3*2*2 x 2*2 = 12 x 4
Fourth: 3*2*2*2 x 2 = 24 x 2
Fifth: 48 x 1
Sixth dimension cannot be integer. So you can for example save this as
48 = 3 * 16 = 1.5 * 2 * 16 = 1.5 * 32
Sixth dimension: 1.5 x 32
NOTE: each dimensions are in feet!
