Calculating Distance Using a Map Scale - Lesson Topic Index | Grade 7 Math | Intermediate Test Prep | StudyZone

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

 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 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

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