Final answer:
The scale factor between the real building and the toy building is 400.
Step-by-step explanation:
To find the scale factor, we need to compare the area of the real building's front side with the area of the toy building's front side.
The area of the real building's front side is 400 square feet and the area of the toy building's front side is 1 square foot.
To find the scale factor, we divide the area of the real building by the area of the toy building:
Scale factor = Area of Real Building / Area of Toy Building
Scale factor = 400 square feet / 1 square foot = 400
Therefore, the scale factor is 400, meaning that the real building is 400 times larger than the toy building.