Given the following question:
Scale factoring a rectangle goes as follows...
You count the number of units on one side, so lets say one of the sides is 2 units long.
1 unit = 6 ft
2 units = 12 ft
To rescale we simply have to double the rectangle in size. So if one side is 6 feet long, the other side will be 12 feet long. Since each corresponding side is equal you only have to calculate two sides.