7.1 - Ratios and Proportions

To write ratios and solve proportions

​What would Barbie look like if she were life-sized?

The producers calculated a ratio

They wanted to find out the comparison of the height of the doll with the height of the average woman in the US.

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A ratio is a comparison of two quantities by division.​

You can express the ratio of the numbers a and b (b ≠​ 0) as:

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Ratios can be simplified.​

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Write each ratio in simplest form:

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Compare three (or more numbers)

In the extended ratio a:b:c, the ratio of the first two numbers is a:b, the ratio of the second two numbers is b:c, and the ratio of the first and third numbers is a:c.

A proportion is an equation that states two fractions are equal.

A proportion is written as:

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​In any proportion, the product of the means is equal to the product of the extremes. Often, people say "cross products are equal".

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