36 has 9 divisors, so there are 5 pairs of dimensions that are possible. Here, we list the smallest dimension first. The numbers in each pair can be used for both (length, width) and (width, length), so there are 9 possible combinations of (length, width).
(1 ft, 36 ft), (2 ft, 18 ft), (3 ft, 12 ft), (4 ft, 9 ft), (6 ft, 6 ft)