Answer:
The diameter of the model is 14.4 inches.
Explanation:
The Diameter of the moon = 2,160 miles
The scale on the model represents 1 in = 150 miles
Let the model represents k inches in 2,160 miles.
So, by the Ratio of Proportionality:

⇒

or, k = 14.4 inches
⇒On the scale 2160 miles is represented as 14.4 inches
Hence the diameter of the model is 14.4 inches.