## Determining the Fractional Scale of a Map or Scale Model

The fractional scale of a scale model is the ratio between two sets of
dimensions (as between those of a model car and its equivalent actual
car). The formula for determining the fractional scale of a map or scale
model is:

1
Scale = _____
AS/MS
Where:
1 = In a fractional scale, the numerator is always "1"
AS = Actual Size
MS = Equivalent Model Size

"AS" and "MS" should be in the same units, e.g., cm, so that the units
will cancel.
Example: If a model car is 20cm long, and the actual car is 3m long, then
what is the scale of the model car?
Step 1. Convert meters to centimeters:
3m = 300cm
Step 2. Calculate scale:
1
__________ = 1/15
300cm/20cm

Therefore, one unit on the model is equivalent to 15 of the same units in
the real world. Every feature on the model is 1/15 of actual size; every
feature on the actual car is 15 times larger than the same model feature.

Copyright © 1997-2012 by Walter Sanford. All rights reserved.

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