Writing a comparison in the form of a ratio
Example
A farmer has 2 cats and 5 dogs. Write down the ratio of cats to dogs and dogs to cats.
Cats : Dogs \(= 2 : 5\)
Dogs : Cats \(= 5 : 2\)
Now try this question:
Question
The same farmer also has 85 sheep and 15 cows. Write down the ratio of cows to sheep in its simplest form.
cows : sheep \(= 15 : 85\)
\(15\) and \(85\) are both divisible by 5
\(\frac{{15}}{5} = 3\)
\(\frac{{85}}{5} = 17\)
So \(15 : 85 = 3 : 17\)
A ratio is used to compare two quantities which are measured in the same units.