Final answer:
The scale factor of 1 in=20 ft can be used to design a site plan by converting the measurements on the drawing to actual dimensions in feet.
Step-by-step explanation:
The scale factor is the ratio of the length on the drawing to the actual length. In this case, the scale factor is 1 in = 20 ft. This means that for every 1 inch on the drawing, it represents 20 feet in real life.
To design a site plan, you can use this scale factor to determine the actual dimensions of objects on the drawing. For example, if a building is represented by a line that is 2 inches long on the drawing, the actual length of the building would be 2 inches * 20 feet/inch = 40 feet.
Similarly, you can use the scale factor to find the actual area of objects on the drawing. If an area on the drawing is 100 square inches, the actual area would be 100 square inches * (20 feet/inch)^2 = 40,000 square feet.