Final answer:
The scale factor of the model to the bookshelf is 3/5.
Step-by-step explanation:
To find the scale factor of the model to the bookshelf, we need to compare the lengths of the model and the actual bookshelf. The length of the model is 3 ft, and the length of the actual bookshelf is 5 ft. We can express this as a ratio: 3/5. This ratio represents the scale factor of the model to the bookshelf.
The scale factor in this case is 3/5.