Final answer:
The scale factor of the new house is 4/3 or 1.33.
Step-by-step explanation:
The scale factor of the new house can be found by dividing the height of the new house by the height of the original house. The height of the original house is 15 feet, and the height of the new house is 20 feet. Therefore, the scale factor is 20/15, which simplifies to 4/3 or 1.33.