Writing RatiosDate: 06/03/99 at 21:09:28 From: Gary Grazioli Subject: Ratios and Rates Write a ratio in three ways. 11 out of 32 students have blue eyes. One way is 11/32. Can you help? Date: 06/04/99 at 08:40:41 From: Doctor Rick Subject: Re: Ratios and Rates Hi, Gary. I can think of two other ways to write this. One is the classic way of writing ratios, using a colon. For instance: The ratio of blue-eyed students to all students is 11:32. Read this as "11 to 32." The other way I have in mind doesn't have the numbers 11 and 32, but it has the same meaning. A percentage is a form of ratio: 10% means "10 out of 100." We can follow the rules for writing an equivalent fraction and make the denominator 100. The numerator won't necessarily be a whole number, so what we get isn't what we normally think of as a fraction, but it is a ratio. 11/32 = ?/100 What do we multiply 32 by to get 100? The answer is 100/32 = 3.125. If we multiply numerator and denominator by 3.125, we get 11 * 3.125 34.375 ---------- = ------ = 34.375% 32 * 3.125 100 In other words, 11 out of 32 is the same ratio as 34.375 out of 100. Here is some further help on ratios from our Archives: What is a ratio? http://mathforum.org/library/drmath/view/58018.html Figuring Ratios http://mathforum.org/library/drmath/view/58012.html Ratios http://mathforum.org/library/drmath/view/58027.html - Doctor Rick, The Math Forum http://mathforum.org/dr.math/ |
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