Calculating Distance Using a Map Scale - Lesson
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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 3 inches, how many actual miles is that?

The proportion would be set up as:


 

x = 3.75 (175)
x = 656.25 or 656 miles

 

Click here for a review on proportions.

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 1265
⅝ 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 2531
miles

Ready to answer some practice problems?

 

 
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