the scale on the map is 1 inch = 200 miles. that is the actual distance between two cities that are 4.5 inches apart on the map

Question

• 1/200:4.5/m

Answer 1

Set up a ratio:  200/1 = x/4.5  (x = actual distance in miles)

4.5 * 200 = x  (multiply both sides by 4.5)

x = 900 miles.  And that makes logical sense if you look at it:  for every 200 miles you have 1" on the map.  So for 4.5" you now have 900 miles.  You can also have other ratios, such as x/200 = 4.5/1

Answer 2

Since 1 inch = 200 miles, then ....

     4.5 inches * (200 miles / 1 inch) = (4.5 inches * 200 miles) / (1 inch) = 900 miles

OR 

     1 / 200 : 4.5 / m     ==>     1 * 4.5 / 200 * 4.5 = 4.5 / 900    ==>    m = 900

Thus, the actual distance between the two cities is 900 miles.