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A scale can be used to indicate the relation between a measure on a drawing and a measure in reality.

The denotation of a scale is like this:


Examples of scales:

1:100 or 1:20000

From drawing to reality

Let's take a look at the scale 1:15000.

That means that 1 inch on the map is equal to 15000 inches in reality.

So if there are 12 inches between two buildings on a map, the distance between the two buildings in reality is:

12*15000=180000 inches=2.84 miles

The general formula for calculating a distance in reality, when the distance on the drawing and the scale is given, is as follows:

measurement in reality=frac{measurement on drawing*scale_{reality}}{scale_{drawing}}

From reality to drawing

Let's take an example with a car, which is 160 inches long.
How long would the car be on a drawing if we should draw it in the scale of 1:50?

measurement on drawing=frac{160*1}{50}=3,2

The car is 160 : 50 = 3,2 inches long on the drawing

The general formula for this calculation is:
measurement on drawing=frac{measurement in reality*scale_{drawing}}{scale_{reality}}

Determination of the scale

Let’s say you know the lengths of a given distance in reality and the equivalent distance on the drawing and you want to determine the scale, you should perceive the denotation scale_{drawing}:scale_{reality} as a fraction.


Presuming that the two given measurements are having the same unit, you just have to substitute them into the fraction as numerator and denominator and then simplify the fraction.

The measurement on a drawing is 10 inches and the equivalent measurement in reality is 5000 feet.
What is the scale?

In this case we must convert the latter of the two given measurements from feet to inches first.

5000 feet = 60000 inches

Then we can calculate the scale:


The scale is: 1:6000


Calculate scales bwtween two measurements