Ratios are used in the real world when there is a need to compare practical values. Ratios are used primarily to determine how much of one object exists in comparison to another. Ratios are used for basic tasks such as cooking and making financial transactions.
Ratios are used to determine specific amounts of substances, such as the different coat colors of animals in a litter or their genders. Ratios are similar to proportions, which also compare two or more objects. Proportions, however, typically involved finding similarities between groups. Proportions may single out only one trait for comparison between groups, such as the difference in litter size between two litters of puppies.