# What is a Hypotenuse (Quick, off the Top of Your Head)? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [August 9, 2013, 5:06am UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782 "2013-08-09T05:06:50Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![garygnu](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garygnu/32/2924_2.png) [@garygnu](https://boards.straightdope.com/u/garygnu)\ **Post date:** [August 9, 2013, 4:18pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/21 "2013-08-09T16:18:09Z")
I have many cheerful facts about the square of the hypotenuse. ---
**Author:** ![Balance](https://avatars.discourse-cdn.com/v4/letter/b/ccd318/32.png) [@Balance](https://boards.straightdope.com/u/Balance)\ **Post date:** [August 9, 2013, 4:26pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/22 "2013-08-09T16:26:51Z")
> [@garygnu](#): > > I have many cheerful facts about the square of the hypotenuse. **shakes fist at garygnu** I had my Major-General reference typed up, and you ninja’d me. grumble…blasted people coming to my desk with work questions when I’m trying to post a joke on the Dope… ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [August 9, 2013, 4:43pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/23 "2013-08-09T16:43:20Z")
> [@DrFidelius](#): > > Sorry, but shouldn’t she be equal to the \*sons \*of the squaws on the other two hides. The way I tell it, she has fraternal twins, one of each sex, while the other two have a daughter and a son separately, so she is equal to the sum of the squaws on the other two hides. ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [August 9, 2013, 4:45pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/24 "2013-08-09T16:45:53Z")
Without reading, a hypotenuse is the side of a right-angle triangle opposite the right angle. How’d I do? ---
**Author:** ![Nava](https://avatars.discourse-cdn.com/v4/letter/n/da6949/32.png) [@Nava](https://boards.straightdope.com/u/Nava)\ **Post date:** [August 9, 2013, 5:26pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/25 "2013-08-09T17:26:08Z")
The side of a\* triángulo rectángulo\* (a triangle with a 90º angle, I don’t know what’s the proper adjective in English) that’s opposite the 90º angle, which is that triangle’s longest side, and whose square is the sum of the squares of the other two sides (which I also don’t know what are they called in English, but the Spanish word is used as an insult meaning “uncultured”). _backs up through the thread, seeing if she can learn a couple new words without cracking open the dictionary_ ETA: now I’m wondering whether English has left triangles 🙂 ---
**Author:** ![Inner\_Stickler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inner_stickler/32/318_2.png) [@Inner\_Stickler](https://boards.straightdope.com/u/Inner_Stickler)\ **Post date:** [August 9, 2013, 5:29pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/26 "2013-08-09T17:29:41Z")
In my geometry class, the sides of a triangle that are not the hypotenuse were always referred to as the legs. (Although usually the three sides were all labeled A,B and C.) ---
**Author:** ![newcomer](https://avatars.discourse-cdn.com/v4/letter/n/e5b9ba/32.png) [@newcomer](https://boards.straightdope.com/u/newcomer)\ **Post date:** [August 9, 2013, 6:00pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/27 "2013-08-09T18:00:32Z")
I wonder how would thread go if you asked what’s the plural of cathetus 😃 ---
**Author:** ![psychobunny](https://avatars.discourse-cdn.com/v4/letter/p/54ee81/32.png) [@psychobunny](https://boards.straightdope.com/u/psychobunny)\ **Post date:** [August 9, 2013, 6:03pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/28 "2013-08-09T18:03:51Z")
The hypotenuse is the side of a right triangle opposite the right angle-I think. ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [August 9, 2013, 6:04pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/29 "2013-08-09T18:04:44Z")
I have no idea what a cathetus is, but I will guess catheti (similar to cactus, cacti) ---
**Author:** ![Lamia](https://avatars.discourse-cdn.com/v4/letter/l/8e7dd6/32.png) [@Lamia](https://boards.straightdope.com/u/Lamia)\ **Post date:** [August 9, 2013, 6:08pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/30 "2013-08-09T18:08:29Z")
> [@Nava](#): > > ETA: now I’m wondering whether English has left triangles 🙂 We call a 90° angle a “right angle” in English, although I don’t know why. I always had the vague idea it was because this sort of angle was more “correct” than other angles. ---
**Author:** ![UncleRojelio](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unclerojelio/32/3160_2.png) [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)\ **Post date:** [August 9, 2013, 6:10pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/31 "2013-08-09T18:10:24Z")
If one if the legs measures 3 and another measures 4, then the hypotenuse is the one that measures 5. ---
**Author:** ![Kamino\_Neko](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kamino_neko/32/34_2.png) [@Kamino\_Neko](https://boards.straightdope.com/u/Kamino_Neko)\ **Post date:** [August 9, 2013, 6:12pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/32 "2013-08-09T18:12:31Z")
The opposite of a hypertenuse, of course. ---
**Author:** ![cochrane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cochrane/32/10441_2.png) [@cochrane](https://boards.straightdope.com/u/cochrane)\ **Post date:** [August 9, 2013, 6:14pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/33 "2013-08-09T18:14:20Z")
> [@DrFidelius](#): > > Sorry, but shouldn’t she be equal to the \*sons \*of the squaws on the other two hides. If she weighs as much as the combined weight of the other two squaws, then the squaw on the hippopotamus is equal to the sum of the squaws on the other two hides. ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [August 9, 2013, 6:24pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/34 "2013-08-09T18:24:52Z")
What if she weighs the same as a duck? ---
**Author:** ![lieu](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@lieu](https://boards.straightdope.com/u/lieu)\ **Post date:** [August 9, 2013, 6:31pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/35 "2013-08-09T18:31:34Z")
It’s one of those old fashined, water-triggered gallows like what they hung Tom Horn with. ---
**Author:** ![cochrane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cochrane/32/10441_2.png) [@cochrane](https://boards.straightdope.com/u/cochrane)\ **Post date:** [August 9, 2013, 6:39pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/36 "2013-08-09T18:39:15Z")
> [@Leaffan](#): > > What if she weighs the same as a duck? Vhy a duck? Vhy-a no chicken? ---
**Author:** ![newcomer](https://avatars.discourse-cdn.com/v4/letter/n/e5b9ba/32.png) [@newcomer](https://boards.straightdope.com/u/newcomer)\ **Post date:** [August 9, 2013, 6:44pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/37 "2013-08-09T18:44:17Z")
> [@PastTense](#): > > I have no idea what a cathetus is, but I will guess catheti (similar to cactus, cacti) And you’d be right 🙂 ---
**Author:** ![standingwave](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@standingwave](https://boards.straightdope.com/u/standingwave)\ **Post date:** [August 9, 2013, 6:49pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/38 "2013-08-09T18:49:11Z")
Without reading any of the thread, my first thought was: \*The side of a right triangle opposite the right angle. \* ---
**Author:** ![california\_jobcase](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@california\_jobcase](https://boards.straightdope.com/u/california_jobcase)\ **Post date:** [August 9, 2013, 6:50pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/39 "2013-08-09T18:50:17Z")
The longest leg of a right triangle ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [August 9, 2013, 7:08pm UTC](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782/40 "2013-08-09T19:08:46Z")
> [@Nava](#): > > The side of a\* triángulo rectángulo\* (a triangle with a 90º angle, I don’t know what’s the proper adjective in English) that’s opposite the 90º angle, which is that triangle’s longest side, and whose square is the sum of the squares of the other two sides (which I also don’t know what are they called in English, but the Spanish word is used as an insult meaning “uncultured”). > > _backs up through the thread, seeing if she can learn a couple new words without cracking open the dictionary_ > ETA: now I’m wondering whether English has left triangles 🙂 The “right” actually comes from the same root as the “rect” in “rectángulo,” namely, the Latin _rectus_, meaning “straight, right.” So, “triángulo rectángulo,” if you broke it down, would be like “right-angled triangle” almost like the English “right triangle.” Of course, a “straight angle” is 180 degrees, while a right angle is 90 degrees, so I’m not entirely sure why a 90 degree angle would take the Latin root for “straight.” [Previous page](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782.md?page=1) [Next page](https://boards.straightdope.com/t/what-is-a-hypotenuse-quick-off-the-top-of-your-head/665782.md?page=3)