Talk:Circle

A Circle have infinite sides

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

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A Circle have infinite sides.Adding this topic expand our perspective. Yuthfghds (talk) 05:34, 2 July 2023 (UTC)

Usually a circle is taken to be a single smooth curve, that is with one curved "side" if you like. However, it is also true that a circle can also be taken as a limiting case of a regular polygon as the number of sides increases without bound. Perhaps this would be worth mentioning in Circle § Limiting case of other figures. –jacobolus (t) 07:04, 2 July 2023 (UTC)

Nah,Circles don't have sides cuz then it would be a polygon.(I think)

So, circles and sides dont Fit in a single sentence. MukulGoyal9999 (talk) 11:28, 7 December 2024 (UTC)

You know that circle has 0 or Infitite Sides.
Right? 12.171.25.60 (talk) 18:38, 16 November 2023 (UTC)

A circle is usually taken to be a single smooth curve. The word "side" is not really precisely defined in the context of smooth curves, so you'll have to define it before you can decide how many sides a circle has. If you consider "side" to mean a straight portion of a curve, then a circle has no "sides". If you consider a "side" to be a smooth (unkinked) portion of a curve, then a circle has one "side". If you consider a "side" to be a straight line tangent to a curve, then a circle has infinite "sides". Alternately, if you like you can consider the circle to be the limiting case of a regular polygon of fixed apothem as the number of sides increases without bound ("infinite sides"). –jacobolus (t) 19:58, 27 November 2023 (UTC)

lol 12.171.25.60 (talk) 16:29, 6 December 2023 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Regions in a circle?

Would it not be better to move discussion of regions (e.g. segment, sector) to the article on discs? 41.133.90.18 (talk) 15:14, 1 December 2023 (UTC)

We could have it in both articles. ISaveNewspapers (talk) 06:56, 30 August 2024 (UTC)

"360 degrees" redirect

Why is this article the redirect destination for "360 degrees"? Wouldn't Turn (angle) be more natural? ISaveNewspapers (talk) 02:53, 30 August 2024 (UTC)

Well, the redirect was created in 2007, so I doubt anyone remembers the rationale. I'd move 360 degrees (disambiguation) to 360 degrees. Apocheir (talk) 03:23, 30 August 2024 (UTC)

Very well. I will also change the redirect to Turn (angle). ISaveNewspapers (talk) 04:13, 30 August 2024 (UTC)

Wait, I can't change the redirect if I also move the disambiguation page. That makes no sense. Sorry, I didn't think this through.

I'd argue that if someone looks up "360 degrees", then Turn (angle) is most likely the place they want to be, so it should redirect there. ISaveNewspapers (talk) 04:18, 30 August 2024 (UTC)

Radians

I'm surprised that radians aren't mentioned a single time in this article, considering that they're pretty important and they're closely connected to circles. I wrote a draft of a short section about radians. I would like feedback about whether this would fit into the article, and if so, where. Also, this definitely needs an image.

If a circle of radius r is centred at the vertex of an angle, and that angle intercepts an arc of the circle with an arc length of s, then the radian measure 𝜃 of the angle is the ratio of the arc length to the radius:

$\theta ={\frac {s}{r}}$

The circular arc is said to subtend the angle at the centre of the circle. The angle subtended by a complete circle at its centre is a complete angle, which measures 2π radians, 360 degrees, or one turn.

ISaveNewspapers (talk) 14:33, 13 September 2024 (UTC)

I agree that it's a conspicuous omission. Maybe in the first part of Analytic Results with Circumference and Area Enclosed, since the circumference and the area of the circle can be generalized to circular arcs and sectors using radians. Apocheir (talk) 21:50, 13 September 2024 (UTC)

Done. ISaveNewspapers (talk) 03:15, 14 September 2024 (UTC)

Equation of a circle

Upper semicircle with radius 1 and center (0, 0) and its derivative.

Would this graphic be an inappropriate addition?

— Preceding unsigned comment added by Ldecola (talk) 01:23, 8 November 2024 (UTC)

yes, i say, so i did it (does anybody read this stuff?)! Lee De Cola (talk) 18:51, 24 January 2025 (UTC)

"Annular form" and "Nexua" at Redirects for discussion

The redirects Annular form and Nexua have been listed at redirects for discussion to determine whether their use and function meets the redirect guidelines. Readers of this page are welcome to comment on these redirects at Wikipedia:Redirects for discussion/Log/2025 March 4 § Annular form and Wikipedia:Redirects for discussion/Log/2025 March 4 § Nexua until a consensus is reached. Duckmather (talk) 16:28, 4 March 2025 (UTC)

Krikos

The krikos etymology is absolute crap. A metathesis would imply a "kirkos" form, which definitely does NOT resemble "kyklos", which is instead derived, through Proto-Hellenic, from Proto-Indo-European "*kʷékʷlos", a duplication of an original root "*kʷel-" (meaning "to turn"). On the other hand, the root of krikos is uncertain but most certainly unrelated to kyklos. Please somebody fix this, I can't since the page is protected. ~2025-32295-09 (talk) 12:03, 9 November 2025 (UTC)

I don't know anything about Homeric Greek. Can you propose a better wording?

Aside: Materialscientist indefinitely protected this page in 2020 due to scattered occasional vandalism. I don't think the indefinite protected status is justified. Materialscientist: can you remove the page protection? –jacobolus (t) 15:43, 9 November 2025 (UTC)

Something like this could do the job: "The word "circle" derives from Latin "circus", of the same meaning, itself a term likely borrowed from Ancient Greek "κίρκος" ("ring, circle"), [which is of unknown further etymology but has been tentatively connected to the Proto-Indo-European root "*(s)ker-" ("to turn, wind")]." ~2025-32366-53 (talk) 16:17, 9 November 2025 (UTC)

Do you know what the relation is between κίρκος vs. κρίκος vs. κύκλος? Maybe it's worth finding a better source specific to Ancient Greek etymology. –jacobolus (t) 23:12, 9 November 2025 (UTC)

I've already written both etymologies, and that proves there being no relation between κίρκος/κρίκος and κύκλος. Kírkos and kríkos are probably from the Proto-Indo-European root *(s)ker- and kýklos is most definitely from *kʷékʷlos. ~2025-32366-53 (talk) 14:44, 10 November 2025 (UTC)

Too much about math

Obviously the circle is an important concept in mathematics. But it also has had a significant impact, culturally. This article largely ignores such and focuses 95% on math with only a brief mention of anything else in the opener.

Here is some AI slop examples:

Gotcha — here’s a short list you can tack onto the end of your talk post:

Analog clock faces as a circular representation of time, still ubiquitous in public and private settings.

Circular traffic and urban design, such as roundabouts and central plazas.

Circular sports equipment, especially balls used in globally popular games (football/soccer, basketball, etc.).

Rings (especially wedding and engagement rings) as everyday symbols of commitment and unity.

Circular logos and emblems widely used in modern branding and international symbolism.

Circular elements in technology and interfaces, such as buttons, icons, camera lenses and control dials.

The circle as one of the first geometric shapes many children are taught to recognize, name, and draw. ~2025-37009-36 (talk) 13:52, 28 November 2025 (UTC)

To the contrary, there is far too little math in this article, which is missing many important aspects of the geometry of one or more circles. However, you should also feel free to research more about cultural or technological uses of circles. Please do your research in reliable sources rather than asking an LLM. –jacobolus (t) 17:14, 28 November 2025 (UTC)

"360 Degrees" listed at Redirects for discussion

The redirect 360 Degrees has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at Wikipedia:Redirects for discussion/Log/2026 February 15 § 360 Degrees until a consensus is reached. Mathguy2718 (talk) 00:38, 15 February 2026 (UTC)

Basics. First.

I'm sorry.. But how is there not even a mention of Pi in the introduction of "Circle"? Is this deliberate? ~2025-43751-48 (talk) 23:15, 8 March 2026 (UTC)

Worse yet, the first mention of Pi is in "Analytics". I think there is a second. That's disturbingly few.

And in the whole article is not one link to https://en.wikipedia.org/wiki/Pi

How? ~2025-43751-48 (talk) 23:19, 8 March 2026 (UTC)

This article is incredibly incomplete, disorganized, poorly sourced, poorly illustrated, etc. It needs probably a hundred or two hours of dedicated effort. Please feel free to do some research and expand it. –jacobolus (t) 23:31, 8 March 2026 (UTC)

@Jacobolus. We already have a planning on the improvement, but left rotten. You want to continue in my sandbox? I'll copied most of them. Dedhert.Jr (talk) 02:34, 9 March 2026 (UTC)