For this case we have:
The area of a rectangle is given by:

Where "a" is the largest side
"b" is the minor side
On the other hand, the perimeter is given by:

If we have:

We must look for two whole numbers not divisible by 6, that when multiplied give 36.
, but 6 is divisible by 6
, but 18 is divisible by 6
, but 12 is divisible by 6
We know that
, 9 or 4 are divisible by 6.

Thus, the perimeter is given by:

Answer:
26cm