Talk:Ratio

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Contents 1 Ratios between more than two quantities 2 Ratios as percentages 3 Comparing ratios 4 Scale map 5 Are ratios necessarily linear? 6 Can Ratios Be Negative? 7 Correctly stating a ratio 8 no chickens!

[edit] Ratios between more than two quantities

I've written an example under the section on ratios and fractions that addresses this issue, I hope.--Dwetherow 05:18, 23 February 2007 (UTC)

Hmmm. I thought you could have ratios between more than two quantities. E.g. If my fruit bowl has apples, pears and bananas in the ratio 1:3:4 and there are 2 apples in there then there are 6 pears and 8 bananas.

So, why does the article limit rations to being between only two quantities? —The preceding unsigned comment was added by 217.22.155.67 (talk • contribs) .

Why wouldn't you just put 2:6:8 ? —The preceding unsigned comment was added by 81.4.160.194 (talk • contribs) .

Usually you try to express ratios in lowest terms. - dcljr (talk) 08:28, 13 April 2006 (UTC)

What you are defining are relative proportions, not a ratio. —The preceding unsigned comment was added by 192.124.26.250 (talk • contribs) .

really —The preceding unsigned comment was added by 71.96.145.159 (talk • contribs) .

Well... it is true that if the fruits are in the "ratio" of 1:3:4 (I have seen this wording in textbooks before), as described above, then the ratio of apples to pears is 1:3, pears to bananas 3:4, and apples to bananas 1:4, so there's nothing wrong with applying the concept of "ratio" to this situation, you just have to think about it two things at a time. Strictly speaking, the word "ratio" refers to a relationship between two quantities only, but proportions (or "proportional" things) can involve any number of quantities (for example, the corresponding sides of any two similar figures are proportional, regardless of how many sides they have). Finally, any ratio can be explained in terms of proportions, as well: if the ratio of pears to bananas is 3:4, then the proportions of pears and bananas, respectively, are 3/7 and 4/7 of the total number of fruits. (And in the previous example, the proportions of apples, pears and bananas are 1/8, 2/8 = 1/4, and 4/8 = 1/2 of the total.) - dcljr (talk) 08:28, 13 April 2006 (UTC)

Therefore a ratio between more than two quantities is a shorthand for expressing several ratios? --72.140.146.246 13:35, 3 June 2006 (UTC)

[edit] Ratios as percentages

Another question. So a ratio can never be expressed as a percentage? —The preceding unsigned comment was added by 202.4.4.48 (talk • contribs) .

If the ratio of apples to oranges is 2 to 1, then the number of apples is 200% (twice) the number of oranges, and the number of oranges is 50% (half) the number of apples. - dcljr (talk) 08:28, 13 April 2006 (UTC)

I think that a ratio is always 100% of everything you are talking about. For example, if you have a 2:1 ratio of apples to oranges then two thirds or approximately 67% of your fruit are apples and one third or 33% are oranges, for a total of 100% or three thirds.--Dwetherow 05:18, 23 February 2007 (UTC)

[edit] Comparing ratios

So if you have two ratios, 1:2000 and 1:4000, which one is "higher"? —The preceding unsigned comment was added by 69.157.57.16 (talk • contribs) .

Well, you divide 1 by 2000, get a number. Then, divide 1 by 4000, get another number. See which one of the two obtained numbers is bigger. Oleg Alexandrov 20:36, 27 September 2005 (UTC)

[edit] Scale map

If you were drawing a map and were using the ratio 1cm:20km how many cm would 22km be? 1.1? —The preceding unsigned comment was added by 81.178.228.183 (talk • contribs) .

Yes. 1 is to 20 as 1.1 is to 22. Or: (1/20)=(x/22) → x=1.1. - dcljr (talk) 06:36, 13 April 2006 (UTC)

[edit] Are ratios necessarily linear?

The article begins by declaring a ratio to be a linear relationship. What about, say, the ratio of a square's perimeter to its area? That's nonlinear; is it a ratio? --VP 38.113.17.3 21:41, 17 April 2006 (UTC)

Yes, I'd like to hear the reasoning for stating that ratios are linear relationships. This implies to me a relationship across the range of magnitudes of a quantity, which is not a (necessary) feature of a ratio. A ratio between two continuous quantities of the same kind is a real number. Ratios between different quantities are not numbers at all. For example 1cm/1g is not a number. However, it is possible to form a ratio between the numbers arising from measurements. You might say that there is a 1:1 correspondence between the volume, say in cm³, and mass, in grams, required to store some material. Then, the ratio is between numbers which are measurements, not between quantities. Holon 01:08, 12 May 2006 (UTC)

1 cm / 1 g is a number, but it is not dimensionless (ie it has units of cm/g). A ratio between, say, the area of two different shapes would give a dimensionless real number (ie no units). --72.140.146.246 19:10, 3 June 2006 (UTC)

1cm/1g is not a number. Take a simpler example; 1g. One gram is not a number: it is a quantity; an amount of mass. The 1 in 1 g is a measure of quantity of mass, and to know its dimension is to know its unit. Quantities themselves are not numbers. Measures of quantities are numbers. Holon 02:16, 4 June 2006 (UTC)

[edit] Can Ratios Be Negative?

Lets say I'm dealing in apples and oranges, and I am in debt apples but have a surplus of oranges.

I may have a ratio of (-2 apples / 3 oranges), and a ratio of (-3 apples / 2 oranges). Which is the larger ratio of apples to oranges?

If thought about as a fraction then -2/3 = -.666, and -3/2 = -1.5.

Therefore, -2/3 is a bigger ratio of apples to oranges because it is 'less negative' compared with -1.5.

However, if thought about in absolute terms, there are more apples to oranges in the -3/2 ratio.

Can ratios work with one (or more) parts of the ratio being negative? Or are ratios strictly absolute?

71.142.81.237 08:11, 22 February 2007 (UTC)Dave A

[edit] Correctly stating a ratio

I have some confusion over ratios and fractions - In the opening statement, the example 2:3 is used and is described as a whole consisting of 5 parts. In the first example, the ratio 1:4 refers to four parts in the whole. Which is the correct description of a ratio? This has always confused me. Stating the question in other terms - if I have a solution consisting of 1 part X and 3 parts Y, do I describe the ratio as 1:3 or 1:4? —The preceding unsigned comment was added by 67.161.203.22 (talk • contribs).

The example was incorrect. To answer your question, the ratio of X to Y would be 1:3 (1 to 3), not 1:4. The proportion of the whole that is X would be 1/4 (one out of 4). I've completely rewritten the article to try to clarify the situation. - dcljr (talk) 19:05, 14 August 2006 (UTC)

I've changed the edits because the concept of ratio is fundamental to the very definition of measurement throughout the physical sciences, and arguably all science. I'm open to debate on how to present the two subtly different usages of the term. Let me know if you have qualms, I'm always open to suggestions Holon 11:07, 16 August 2006 (UTC)

[edit] no chickens!

someone added the word 'chicken' to the start of the page. it wasn't in context and i assume it was a mistake so i removed it. if you're terribly fond of chickens and find this edit to be offensive, i apologize.

gba 05:11, 12 February 2007 (UTC)

I'm sorry. I don't edit and don't know what the standards are involved. I just wanted to point out something I think needs correction:

Under: Ratios and fractions

"a) If you have three apples for every four oranges then you have a 3:4 ratio b) If you want to determine what fraction of the total fruit will be apples or oranges then you add the parts of the ratio to determine the total fruit, in this case: 3+4=7 c) The total fruit becomes the common denominator and the parts of the ratio become the numerators, in this case: 3/7 of the fruit are apples and 1/7 are oranges d) The fractions implied in a ratio will always total one whole (or 100% of the fruit), in this case: 3/7 + 4/7 = 7/7 = 1"

Specifically "c) The total fruit becomes the common denominator and the parts of the ratio become the numerators, in this case: 3/7 of the fruit are apples and 1/7 are oranges" I believe the "1/7 are oranges" should read "4/7 are oranges"

24.61.93.51 15:30, 17 March 2007 (UTC)peter