Final answer:
Scale can be represented by a ratio or inches per foot. Scale factor is used to determine the relationship between scale dimensions and actual dimensions.
Step-by-step explanation:
Scale can be expressed either by a ratio or by inches per foot. A scale factor is a ratio that compares scale dimensions to actual dimensions. It is used to determine the relationship between the scale dimension and the actual length. For example, if 3 inches is equal to 12 feet, the scale factor would be 1:4.