You can put this solution on YOUR website! If the dimensions are limited to integers, then:
you want the longest (most un-square like) rectangle possible for greatest perimeter.
64 cm x 1 cm
A = 64 x 1 = 64 cm^2
P = 2(64) + 2(1) = 130 cm
You can put this solution on YOUR website! What is the greatest perimeter of a rectangle with area 64 cm2?
----------------
There is no greatest perimeter.
It might be 0.001 cm by 64000 --> 128000.002 cm
----------
Or 0.000001 by 64,000,000, etc