Read both definitions. Pay attention to the units that are being compared in each definition.
See solution.
Practice makes perfect
Let's start by writing the concept of scale of a model.
The scale of a model or drawing is the ratio of a length on the model or drawing to the actual length of the object being modeled or drawn.
Similarly, let's write what the scale factor of a model is.
The scale factor of a model or drawing is written as a unitless ratio in simplest form. They are always written so that the model length in the ratio comes first.
From the definitions we can see that both scale and scale factor can be written as ratios comparing lengths. However, a scale factor must have the same unit of measure for both measurements while the scale could compare two different units of measure.
Notation
Interpretation
Scale
1 in :5 ft
1 inch in the drawing represents 5 feet in the actual model
Scale factor
1: 2
1 unit in the model represents 2 units in the actual model
