How to Find Ratios

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A ratio is a way of comparing the quantity, amount or size of two or more things. Using the following information, you will learn how to find a ratio and how to write it three different ways: A pet store has 8 dogs, 10 cats and 15 birds.

Find the Ratio of Birds to Cats

    Pay close attention to the order of things you are comparing; the ratio must be written in the same order. There are 15 birds and 10 cats, so the ratio is 15 to 10. You can also write this as 15:10 or 15/10.

    Simplify the ratio. Notice that 15/10 is a fraction. Remember that to simplify fractions, you divide both numerator and denominator by the greatest common factor (GCF). Dividing both 15 and 10 by 5 gives you the simplified fraction 3/2. 15 to 10 becomes 3 to 2, and 15:10 becomes 3:2.

    Restate the question in the answer to be sure that you put things in the right order. "The ratio of birds to cats is 3:2." What this means is that for every three birds in the store, there are two cats.


    • A ratio can be either a proper fraction or an improper fraction.


    • Word problems often provide extra information. Don't think you must use all of the numbers just because they are there.

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