On a particular road map, 1/2 inch represents 18 miles. About how many miles apart are 2 towns that

On a particular road map, 1/2 inch represents 18 miles. About how many miles apart are 2 towns that are 2 1/2 inches apart on this map?

A) 18
B) 22 1/2
C) 36
D) 45
E) 90

Set up a proportion of inches to miles where m is the number of miles for 2 1/2 inches. Note: 1/2 = 0.5 and 2 1/2 = 2.5
0.5/18 = 2.5/m

Typing this proportion into the search engine, we get:
m = 90 Answer E