When reading a map, it is important to know how to
read a map scale.
For instance, if 1 inch equals 100 miles and the
distance from one city to another is 4 inches on the map, the actual
distance is 400 miles.
We mentally set up a
proportion to solve this. However, not all proportions are this
simple. If you have a fractional measurement it may be easier to
convert it to a decimal before doing the work.
Let's say a map scale is 1
inch = 175 miles.
If the distance on the map
from one city to another is 3¾
inches, how many actual miles is that?
The
proportion would be set up as:
x = 3.75 (175)
x = 656.25 or 656¼ miles 
1 inch = 225 miles
You measure the distance from
one city to another to be 5⅝
inches. What is the actual distance in miles?
x = 225 (5.625)
x = 1265.625 or 1265⅝
miles 
One more...
1 inch = 810 miles
You measure the distance from
one city to another to be 3⅛
inches. What is the actual distance in miles?
x = 810 (3.125)
x = 2531.25 or 2531¼
miles 
Ready to answer some
practice problems?
