What is the maximum area of rectangle whose perimeter is 18 cm.?

Dear Student, 

  We Know that, Perimeter = 2 * ( L + B )
                        ( L + B ) = 9
  Let us assume that the possible cases of L * B are :
                5 * 4 = 20
                6 * 3 = 18
                7 * 2 = 14
                8 * 1 = 8
Hence, the maximum area is 20 cm² .

Hope this information clears your doubts.

Regards