Gable roof install on a different length side wall garden building?

[ghost32]

Looking for ideas on roofing a uneven garden building that will be housing a hot tub.
dimension of building are as follows

3.6 x 3.6 x 3.6 x 4.7 (m)
wanted to keep costs and carpentry low and put a gable
issue is the 4.7 is one of the sides
is this still possible?
or do I need to think about Hip or pyramid
Ideally I need to keep the pitch as low as possible..

 

[noseall]

do I need to think about Hip or pyramid
.

Flat.

 

[datarebal]

small out of square flat roof at the top .