# What are scales in math?

mrsmott | Certified Educator

Scales as related to ratio? Or scales as related to maps?

If you are looking at a way to understand scales, they are a way to take something "really, really" big and represent in a way you can "see" it. For instance, if an inch on the map equals 100 miles, then you would measure the distance on the map and set up the ratio of 1 inch is to 100 miles and the distance you measure is to X miles. Then cross multiply and divide to get the "actual" miles. Artists use the golden ratio and proportions to get their art to scale with the real deal. If you have done model cars, they are on scale, so that if you blow up the actual model car 250 times, it will be the size of the real car it represents.

I have included some links below that might help you better understand scale. I am not sure of your level in school, so some may be too elementary for your needs. If you replace the word "scale" with "ratio" or "proportion" and do an Internet search for interactive activities it might help. You may also want to watch "Donald in Mathmagic Land," an old Disney movie that has a good visual explanation of scale.

revolution | Student

They are linear scales represented in maps or diagrams, a line marked at interval points to show the distance of an object compared to the distance on the scale it represents:

Like 20 cm is to 1m or 100cm, scale ratio

Simplifying the scale ratio, it will be:

20cm:1m= 20cm:100cm

= 20:100

= 1:5 or 1/5.

If you get a X miles of distance of object, for example 40cm you can use direct proportion (scale ratio), which is 1:5 to get the Y miles of distance on scale. Just cross multiply the fractions (change ratios to fractions first) then solve the equation to get the Y value

Scale ratio= 1:5, and you got X miles, and you need to find Y miles, so:

40/Y= 1/5

Y=40*5=200 cm on scale.