Let us try to understand the ratio with an example. In a cake recipe, we require 4 cups of flour, 2 cups of milk, and 1 cup of sugar. The ratio of flour to milk used in the cake is 4∶2. Similarly, the ratio of flour to sugar is 4∶1. The ratio is used to show a comparison between two quantities.
In a class, there are 25 students out of which 10 are boys and 15 are girls.
The ratio is represented by the symbol “∶” or the word “to”. The ratio is nothing but a fraction. Therefore, we can reduce the ratio to the lowest term.
\(10∶15 = \frac{10}{15}= \frac{2}{3} \)or 2∶3
\(10∶25= \frac{10}{25} = \frac{2}{5} \)or 2∶5
If we want to make a cake of a bigger size, how many cups of milk and sugar should be used with 8 cups of flour? Here the ratio of milk to flour should be the same as earlier, therefore
\(\displaystyle \frac{4}{2} = \frac{8}{?}\)
Proportion denotes that the two ratios are equal.
\(\displaystyle ?=\frac{2\times8}{4}\)
\(? = 4\)
Therefore if 8 cups of flour are used, then 4 cups of milk and 2 cups of sugar are required.
