Talk:Ratio

Content-less picture

I agree on the pic not having much information. Nevertheless, I appreciate to have any pic, somehow related and nicely rendered, at the top of a page. It appears as a mouse-over, confirming a suitable link, it attracts the focus when getting rendered, it primes the thoughts when seen, ... Any article looks to me more inviting by far, if there is a pic at the top, and if the lead does not start right out with frightening math prose. Certainly, not for all math topics there are suitable pics, but this saturated red spot, depicting a well-known ratio, signalizes a welcome with an almost historic ratio.

I hope you do not mind my cheekiness of inserting the pic (I really have no personal relation to it) at a place with related content, but I honestly estimate the looks of the article higher, when having the pic atop - really better than an info-box in this case. May I ask to reestablish it at the previous place? Purgy (talk) 16:28, 6 March 2019 (UTC)

For no reply I restored the long standing status of a pic before the recent edits. Purgy (talk) 14:55, 10 March 2019 (UTC)

Why SD television?

Why is the aspect ratio of SD television given so much prominence, especially considering that it's 2020 and that the article has no other illustrations? There are much better aspect ratio pictures on Commons and I don't think a general article about ratios should focus on television so much. What about paper? What about ratios in nature? Or architecture? — Preceding unsigned comment added by 2A02:A457:9497:1:F938:499E:52BC:CB4C (talk) 11:33, 25 April 2020 (UTC)

Please sign all your talk page messages with four tildes (~~~~) — See Help:Using talk pages. Thanks.

"SD television" (your title) is nowhere mentioned in the article. The word television appears twice, once as the caption of the illustration, and once very briefly. So, I don't think that the article focuses on television at all. But feel free to pick another illustration. - DVdm (talk) 12:35, 25 April 2020 (UTC)

Notation for ratio

In edit 1122988576, Peter M. Brown tagged the description of ratios as using the colon character with a Template:Citation needed. At first I thought that the concern was needing a citation for the use of U+003A : COLON over U+2236 ∶ RATIO, but then I saw that this wasn't the case. My second impression was that they wanted a citation that the colon notation is at all common—and I thought they must be having a bit of a laugh, questioning whether the notation that's constantly present throughout the entire article is really used!

Then I finally slowed down and looked more carefully at what they actually wrote: The questionable implication is that a ratio is more commonly presented in the A:B form than as a fraction or percentage. And this leaves me somewhat bewildered, as I don't read the statement in question in that way at all. I read it as "when the A:B form is used, the two-dot character is a colon", not "the A:B form is a more common way to compare two quantities than fractions or percentages". But perhaps because I don't read it that way, I'm not sure how to rephrase the sentence so as to not give that impression. Any ideas? -- Perey (talk) 14:31, 23 November 2022 (UTC)

If the sentence is taken to mean "When the A:B form is used, the two-dot character is a colon", a supporting citation is still required. The fact than the colon is "constantly present throughout the entire article" does not imply that it's common elsewhere. Peter Brown (talk) 23:34, 24 November 2022 (UTC)

I'm not sure I agree—it seems like WP:BLUESKY to me. I recognise that there's fair grounds for dissent there, though, and so I shall try and find a suitable reference to cite.

But that's beside the point. My question isn't about what needs to be cited. It's evidently possible to misunderstand the sentence as "ratio-with-colon is more common than fractions or percentages", and I would like it to be rewritten to avoid that issue. I'm not sure how, though, and that's what my question is about.

How about this?

When written in the form A:B, the two-dot character is usually the colon punctuation mark (U+003A : COLON).^{[insert citation here]} Unicode also provides a dedicated ratio symbol, U+2236 ∶ RATIO.

-- ::Perey (talk) 03:55, 26 November 2022 (UTC)

@Peter M. Brown: Regarding your change of wording from "is usually the colon" to "is sometimes the colon". I disagree with your statement in the edit summary, "The cited source does not support the stronger claim." On the contrary, I think the source does not support the weaker claim. It says, "The colon is the symbol ':'... [used to] denote ratio" (emphasis mine). No ifs or buts, no hedging. Even my use of "usually" was a mistake here!

I think the issue might be a confusion between "the symbol is the colon" and "the symbol is U+003A : COLON". I'm not sure I can explain this well, but let me try. The former is the abstract identity of the character; the latter is its concrete computer encoding. For comparison:

• The "baseline dot" symbol for a decimal point is the same as the full stop punctuation, in both senses. It's the same character (abstract), and it's encoded as U+002E . FULL STOP (concrete).
• The "horizontal line" symbol for a negative number is abstractly different from hyphen or dash punctuation, even if it's concretely encoded as U+002D - HYPHEN-MINUS (rather than Unicode's preferred U+2212 − MINUS SIGN).
• The "two dots" symbol for ratio is abstractly the same as the colon punctuation. Its concrete encoding can be the same, or you can follow Unicode's recommendation and use U+2236 ∶ RATIO. (Contrast the same symbol for separating time units, as in "23:45", which is a colon in both senses—you wouldn't use U+2236 for that.)

(In all cases, I am leaving aside the possibility of choosing an entirely different symbol for the same meaning. A comma could be used for a decimal point, a commercial minus sign for negative numbers, a fraction bar for a ratio, or a dot for a time separator.)

Anyway, I think the MathWorld source is a pretty clear statement that the mathematical sign and the punctuation colon are considered the same—no "usually" or "sometimes" about it. (And what else would it be, anyway?) -- Perey (talk) 13:01, 27 November 2022 (UTC)

The source says of the colon that it is the symbol ":" and that it "is used in a number of different ways in mathematics." The source goes on to list seven ways that it is used, one being "To denote ratio or odds, as in 2:1". The source does not say that it is the symbol used to denote ratio or odds, excluding other symbols. One might as well infer from

Iron is the element most abundant on earth

and

Iron is used in the construction of automobiles

that

Iron is the element used in the construction of automobiles

as of course there are others, carbon for example.

All that one can conclude from Perey's source is that the colon is used—sometimes—to denote a ratio. Perhaps not often, perhaps not usually, but sometimes. Peter Brown (talk) 22:53, 27 November 2022 (UTC)

Indeed, your hypothetical source doesn't support a claim that only iron is used, to the exclusion of all other elements... but it does support a claim that iron is always used. An exception (a completely iron-free car) would then be the unusual case requiring a citation.

As applied to the present case: The notation "A:B" is not used to the exclusion of other notations (fractions et al.), but when it is used, that two-dot symbol in the middle is a colon. That's what I believe to be true, that's what I read the MathWorld source to say, and that is all that I intended to say with the sentence in the article. And I think that your implication that it could be some other two-dot symbol, not identifiable with the colon, is then the extraordinary claim that you need to cite. -- Perey (talk) 00:03, 28 November 2022 (UTC)

Perey's claim is that "[W]hen it [the notation A:B] is used, that two-dot symbol in the middle is a colon." We need to clarify just what constitutes such a use. If uses consist only of expressions made up of two numerals with a colon between them, then—trivially—the symbol in the middle is always a colon. If, more broadly, we count other expressions made up of two numerals between which is a mark consisting of two dots aligned vertically, then "2∶3", involving the Unicode ratio symbol, is also a use. On that interpretation, the claim is incorrect.

The MathWorld source is devoted specifically to the colon, so it has nothing whatever to say about expressions, like "2∶3", that lack colons. The source does support the claim that the colon is sometimes used to indicate a ratio. It does not support Perey's stronger claim. Peter Brown (talk) 23:42, 29 November 2022 (UTC)

Ah, now we come to the question that I was describing—no doubt inadequately—as “abstract vs concrete”. See, to my mind, that is a colon. The fact that it’s encoded as U+2236 ∶ RATIO doesn’t change that. Compare:

• Which of these use a minus (subtraction) sign to denote a negative?
  -2, −2, –2, $-2$, ⁻2, ⁒2, (2), 2
  My answer is “the first four or five”, even though three of them are different Unicode characters (one an en dash, which isn’t proper), and one is an image, not characters at all. The fifth is arguable; is a superscript minus sign still the same notation?
• Which of these use a slash to denote a fraction?
  1/2, 1⁄2, 1∕2, ½, ${\frac {1}{2}}$
  My answer is “the first four”. (The second is U+2044 ⁄ FRACTION SLASH, and the third is U+2215 ∕ DIVISION SLASH.)
• Which of these use a colon to denote a ratio?
  1:2, 1∶2, $1:2$, 1 to 2, ${\frac {1}{2}}$
  My answer is “the first three”.

Another thought: when I handwrite 1, two dots, 2, is that a colon? -- Perey (talk) 02:06, 30 November 2022 (UTC)

I changed the article text from

When a ratio is written in the form A:B, the two-dot character is usually the colon punctuation mark

to

When a ratio is written in the form A:B, the two-dot character is sometimes the colon punctuation mark

claiming, in my edit summary, that the cited source does not support the stronger claim. Perey said that the source does not even support the weaker claim. What is the situation if "colon" interpreted as in his latest exposition?

What is it for an expression to have the form A:B? Perey's current view, I think, is for it to be made up of two expressions separated by a mark consisting of two dots vertically aligned. And what is it to be a colon? Isn't Perey's view that it is to be a mark consisting of two dots vertically aligned, whether U+003A : COLON, U+A789 ꞉ MODIFIER LETTER COLON, U+2236 ∶ RATIO, or something else?

So the sentence that I changed, on Perey's reading, is equivalent to:

When a ratio is written as two expressions separated by a mark consisting of two dots vertically aligned, then the two-dot character is usually a mark consisting of two dots vertically aligned.

Since this is true in all possible worlds and remains so if "usually" is replaced by "sometimes", whether the source supports it is not an issue. It's WP:BLUESKY and doesn't belong it a Wikipedia article with or without a source.

Peter Brown (talk) 21:10, 30 November 2022 (UTC)

Certainly, if you replace a word with its definition, then a definition of that word becomes tautological. That doesn't mean we can't define things in Wikipedia. (Surely WP:BLUESKY is something else, though? Not "don't state obvious things", but "don't demand citations for obvious things".)

I think it's become clear that the section doesn't do a satisfactory job of saying what either of us wants to say. Forgive me if I am putting words in your mouth, but I gather that you want it to say "the notation A:B sometimes uses U+003A : COLON". I want it to say "a ratio can be written with a colon, as A:B". These are not contradictory statements, and in fact they can and should both be included. (Indeed, they already are, but clearly not in a satisfactory way.) I'm going to go away and consider how the whole section can be reorganised to better express both facts. -- Perey (talk) 00:20, 1 December 2022 (UTC)

Split Proportion (mathematics)

Please discuss at Talk:Proportion (mathematics)#Split. fgnievinski (talk) 18:43, 17 March 2023 (UTC)

Initial description of ratio is poor and is not matched by the example

The opening line is "In mathematics, a ratio shows how many times one number contains another."

The example given is "if there are eight oranges and six lemons in a bowl of fruit, then the ratio of oranges to lemons is eight to six" But while the bowl (total 14 fruit) contains 8 of one and 6 of the other, six does not 'contain' eight and of course eight _oranges_ cannot 'contain' six lemons. A better short description would be "a ratio shows the relative size of two numbers" SLR Ellison (talk) 10:43, 16 February 2024 (UTC)

To the best of my understanding, the word "ratio", from translations of Euclid's Elements, originally meant something like an ordered pair of related quantities (for instance two specific geometric lengths, or two specific numbers). Two ratios $a:b$ and $c:d$ were said to be in "geometric proportion" (a few centuries ago this was denoted $a:b::c:d$) if $ad=bc,$ or were said to be in "arithmetic proportion" if $a+d=b+c.$ More recently, the concepts of "ratio" and "two ratios in geometric proportion" have often been conflated, so that the word "ratio" often means something more like «the equivalence class of pairs of quantities $x:y$ such that $x_{1}:y_{1}$ is equivalent to $x_{2}:y_{2}$ whenever $x_{1}y_{2}=x_{2}y_{1}.$». In my opinion the current article doesn't do a very good job of describing this though. –jacobolus (t) 14:32, 16 February 2024 (UTC)