Talk:Isosceles triangle

Isosceles triangle has been listed as one of the Mathematics good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.

Article milestones
Date	Process	Result
September 13, 2018	Good article nominee	Listed
A fact from this article appeared on Wikipedia's Main Page in the "Did you know?" column on November 1, 2018. The text of the entry was: Did you know ... that decorative patterns using isosceles triangles* date back to the Early Neolithic?*

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Etymology

Can we add the etymology of the word 'isosceles' here? Googling I found that it was "isos ‘equal’ + skelos ‘leg’". I think it aids understanding. Chockyegg (talk) 15:40, 9 October 2014 (UTC)[reply]

Usages

Page Punta Cruz Watchtower refers to a "perfect isosceles triangle". Does that mean anything? 112.198.82.241 (talk) 03:17, 20 October 2014 (UTC)[reply]

I think it's just intended to mean "as opposed to a triangle with two sides nearly equal". Loraof (talk) 16:21, 9 September 2015 (UTC)[reply]

ipa?

. — Preceding unsigned comment added by 62.235.179.44 (talk) 08:34, 27 March 2016 (UTC)[reply]

GA Review

This review is transcluded from Talk:Isosceles triangle/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Fearstreetsaga (talk · contribs) 19:34, 11 September 2018 (UTC)[reply]

The article was a good read. Here are my suggestions:

Terminology, classification, and examples

"isosceles sets, sets of more than three points in which every triangle is isosceles" Based on the definition provided in the reference, an isosceles set could have three points. This also does not make it clear where these triangles come from; consider rewording this to make it more clear that any three points in the set form an isosceles triangle.
- Done —David Eppstein (talk) 21:38, 12 September 2018 (UTC)[reply]

Perimeter

"In the equilateral case (when the isoperimeteric inequality becomes an equality) there is only one such triangle, which is equilateral." Mentioning equilateral twice here is repetitive. We know the triangle is equilateral because we are considering the equilateral case.
- Done —David Eppstein (talk) 21:38, 12 September 2018 (UTC)[reply]

Angle bisector length

"The 30-30-120 isosceles triangle makes an interesting test case" Remove the point of view
- Done —David Eppstein (talk) 21:38, 12 September 2018 (UTC)[reply]

Radii

I'd recommend indicating that the purple line is the symmetry axis in the image, since it is referenced in this section.
- Done —David Eppstein (talk) 21:38, 12 September 2018 (UTC)[reply]

In architecture and design

"so-called Egyptian isosceles triangle" Replace or remove so-called per MOS:Words to watch
- Done —David Eppstein (talk) 21:38, 12 September 2018 (UTC)[reply]

History and fallacies

"Others claim that the name stems" Replace claim per MOS:Words to watch
"but W. W. Rouse Ball claims priority in this matter" What do you mean by this?
- Done. Rewrote the pons asinorum etymology to focus on the actual theories of its etymology and avoid saying that vaguely identified people claimed things, and clarified Ball's claim. —David Eppstein (talk) 06:22, 13 September 2018 (UTC)[reply]

Notes

"Some other sources claim" Same as above
- Done. This was the toughest one to handle, because I don't want to list publications in the references section (implicitly saying that they're good references to the subject) only to say somewhere else that they're actually not so good, and I don't think we need to point fingers at authors of discredited theories. But I found a recent and impeccable source (Clagett) who attributes the "some other sources" claim more specifically to "many of the early Egyptologists" so I went with that as a direct quote. —David Eppstein (talk) 06:53, 13 September 2018 (UTC)[reply]

References

The link to the article by Whitney Smith is dead. Fearstreetsaga (talk) 19:34, 11 September 2018 (UTC)[reply]
- Done —David Eppstein (talk) 00:52, 13 September 2018 (UTC)[reply]

@Fearstreetsaga: Ok, I think I've handled all the points you mentioned above. Anything else to do? —David Eppstein (talk) 06:53, 13 September 2018 (UTC)[reply]

@David Eppstein: Everything looks good. I'll go ahead and pass the article. Congratulations. Fearstreetsaga (talk) 13:24, 13 September 2018 (UTC)[reply]

Bold in lead

Why is there so much bold in the lead section? Didnt3a (talk) 10:05, 10 October 2021 (UTC)[reply]

There isn't anymore. ~Anachronist (talk) 21: 07, 8 December 2022 (UTC)

Internal similarity

I wanted to point out a feature of isosceles triangles but am not sure where it would fit.

If you draw a line perpendicular from any side of an isosceles triangle to the opposite corner, the triangle is subdivided into two similar right triangles. These two triangles are congruent if the perpendicular line is drawn from the iscosceles base. ~Anachronist (talk) 21:12, 8 December 2022 (UTC)[reply]

Lewis Carroll died at the beginning of the year 1898.

How could he publish something in 1899? This is a clear mistake, at least unclear information, since there is no reference. If this refers to "Curiosa Mathematica", then it has to be 1890. So I guess it is a typo. 46.114.146.99 (talk) 08:40, 28 February 2023 (UTC)[reply]

The Lewis Carroll Picture Book was published posthumously. The specific section here was originally intended to be part of Curiosa Mathematica part 3, which was never completed. –jacobolus (t) 04:41, 5 January 2024 (UTC)[reply]