Figuring RatiosDate: 08/07/97 at 21:16:01 From: Licia Subject: Ratios How do you figure the ratio of something? I learned how in 6th grade, but the information was never used and so I forgot. I really don't know if Pre-Algebra uses ratios but I would just feel better if I knew. Can you please help me? Licia Date: 08/08/97 at 08:36:29 From: Doctor Jerry Subject: Re: Ratios The word ratio means different things to different people. I suspect that different mathematics texts have slightly different meanings attached to the word "ratio." A ratio is usually a quotient of two numbers, like 2/3. If you have a classroom with 12 girls and 18 boys, then the ratio of girls to boys is 12/18 = 2/3. The ratio of boys to girls is 18/12 = 3/2. If you go into another classroom and someone tells you that the ratio of girls to boys is 3/7 and that there are 21 boys, you can figure out the number of girls. The ratio is g/21 and we know that this is 3/7. So, g/21 = 3/7. g = 9 People say "the odds are 5:3 that a certain horse will win." This terminology is related to ratios. In particular, 5:3 is associated with the ratio 5/(5+3) = 5/8. On average, the horse will win 5 out of every 8 races. When you calculate a ratio, the two things must have the same units. If you have a rectangular field that is 240 feet on one side and 20 yards on the other, it is a mistake to take the ratio of 240/20 in an attempt to compare the two sides. -Doctor Jerry, The Math Forum Check out our web site! http://mathforum.org/dr.math/ |
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