A certain region has a population of about 806,329 people, and a population density

Hey there!

We can utilize division and fractions to find the original scale and the new scale of this situation. 

For the original scale:

, meaning that for every 18 inches on the map, the length of the courtyard would measure 54 feet

We can divide this fraction by a greatest common factor of 18 to get it to:

, meaning that for every 1 inch on the map, the length of the courtyard would measure 3 feet

For the new scale:

, meaning that for every 18 inches on the map, the length of the courtyard would measure 72 feet

We could also divide this fraction by a greatest common factor of 18 to get it to:

, meaning that for every 1 inch on the map, the length of the courtyard would measure 4 feet

So, the scale went from  to , or from 3 feet in the first scale to 4 feet in the second scale. 

Your answer will be D. 

Hope this helped you out! :-)