Question 411818
The largest area is given by a square design

let us analyse
perimeter is 24
each side 6ft

we can have width 1 length 11  area 11
            width 2 length 10  area 20
                  3 lenght 9    area 27
                  4  length 8   area    32
                  5  lenght 7   area 35
                  6  lenght 6   area 36
 we do not need to go further as width 5 lenght 7 will be above also