Answer :

VzDeath
It's length and width are:
l=6
w=2
or
l=2
w=6
iGreen
There are many different combinations.

We just need two numbers that when you multiply them you get 12.

We can have:

Length = 1
Width = 12

Length = 12
Width = 1

Length = 2
Width = 6

Length = 6
Width = 2

Length = 3
Width = 4

Length = 4
Width = 3