Question

How are scales and ratios related?

Answer 1

A scale is always in the form `1 : n`

A ratio compares two or more quantities.

Explanation:

A scale is a specific type of ratio.

It compares a unit on a map or plan or on a scaled model to an actual distance on a map or the size of a real object.

A scale is given in the form: `" "1" ":" "n`

On a map, a scale of `" "1:50" "` means

`" "1cm` on the map represents `50cm` on the ground (in reality)

or `" "200mm" "` on a plan to this scale, indicates a length of
`200xx50=10,000mm` in reality.

A ratio is a comparison between two or more quantities of the same type.

e.g: girls : boys are in the ratio `4:3` means that:

for every `4` girls there are `3` boys.

If there are `35` children in a class with this ratio, we have:

`4/7` of the class are girls (which means `4/7 xx35 = 20` girls.)

`3/4` of the class are boys (which means `3/7xx35 = 15` boys.)