How are scales and ratios related?

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Answer 1 · 2018-05-30T11:29:19

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

A ratio compares two or more quantities.

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: $1 : n$ $" "1" ":" "n$

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

$1 c m$ $" "1cm$ on the map represents $50 c m$ $50cm$ on the ground (in reality)

or $200 m m$ $" "200mm" "$ on a plan to this scale, indicates a length of
$200 \times 50 = 10, 000 m m$ $200xx50=10,000mm$ in reality.

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

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

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

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

$\frac{4}{7}$ $4/7$ of the class are girls (which means $\frac{4}{7} \times 35 = 20$ $4/7 xx35 = 20$ girls.)

$\frac{3}{4}$ $3/4$ of the class are boys (which means $\frac{3}{7} \times 35 = 15$ $3/7xx35 = 15$ boys.)