How is finding the number of ways to model a rectangular house related to finding factor pairs

If you know the square units of the house, and you find the factors, that is the different ways to place the house, ex. if you have a house that is 200 square units, and you get the factors, 200x1, 100x2, 50x4, 25x8, 20x10 5x40 then you have 6 ways, and if you turn the factors around you have another 6 ways, so there are 12 ways to put that house down.