Timeline for Definition of Trapezoid
Current License: CC BY-SA 4.0
23 events
| when toggle format | what | by | license | comment | |
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| Jan 26, 2021 at 12:44 | comment | added | Amy B | I write questions for math tests for elementary schools. I have been told to stay away from trapezoids because of the conflicting definitions. | |
| Jan 26, 2021 at 12:28 | comment | added | Gerald Edgar | In elementary calculus, we teach something called the "trapezoidal rule". But in fact, some of those trapezoids could be rectangles or even squares. For that purpose, it is useful to think of rectangles (and squares) as special trapezoids. | |
| S Jan 26, 2021 at 4:10 | history | suggested | CommunityBot | CC BY-SA 4.0 |
added image description & transcription for accessibility
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| Jan 26, 2021 at 3:40 | review | Suggested edits | |||
| S Jan 26, 2021 at 4:10 | |||||
| Jan 26, 2021 at 3:27 | answer | added | Jeffrey | timeline score: 2 | |
| Jan 26, 2021 at 0:53 | vote | accept | JTP - Apologise to Monica | ||
| Jan 25, 2021 at 23:03 | comment | added | Kuba hasn't forgotten Monica | And I do agree that there often isn't the one and true definition, as is the case here, but even then schoolbooks come last. If a teacher truly has to confront two opposing definitions from reputable sources, then it's a nice teachable moment, but I'd personally never consider a high school (or any other grade school) math text to be reputable unless there was nothing else available (some island cut off from the world, and even then I'd like to trust my memory first). School books are that bad. American ones, Polish ones, I'm sure the lot of them are really done with zero love of the craft. | |
| Jan 25, 2021 at 23:00 | comment | added | Kuba hasn't forgotten Monica | I'm of a firm belief that there's a whole bunch of "knowledge" that only exists to fill up grade textbooks and not only is not found anywhere outside said textbooks, and is of no use but to punish students who find alternative sources of information. Personally, as a student 30 years ago, I'd refer to some well-regarded math encyclopedia. These days it could be mathworld.wolfram.com/Trapezoid.html, and go with what's there, and basically tell the teacher a polite equivalent of "put up or shut up". As far as references go, school textbooks come last. In some cases even after Wikipedia. | |
| Jan 25, 2021 at 17:27 | comment | added | supercat | @DarrelHoffman: In many cases, it is useful to have both exclusive and inclusive terms for things, such as "irrational numbers" versus "real numbers". If the definition of "trapezium" is as stated, then "trapezoid" and "trapezium" would have usefully distinct meanings, with the former being exclusive and the latter, inclusive, which seems more useful than trying to treat the words as synonymous and arguing about whether it should be exclusive or inclusive. | |
| Jan 25, 2021 at 17:11 | comment | added | Darrel Hoffman | @supercat I think the general rule is to always use the most specific term that applies. You could call a parallelogram a "trapezoid", but it's a special case of trapezoids, so you'd use the more specific term. Just like you could call a square a rectangle or a rhombus (since it is in fact both, as well as a parallelogram, trapezoid, and kite by extension), but you use the more specific term since it's a special case. Just like "Snoopy is a beagle, a beagle is a dog, a dog is a mammal, a mammal is an animal, an animal is a living organism, etc." It applies in any field. | |
| Jan 25, 2021 at 16:26 | comment | added | supercat | As an American, I've only heard the term trapezoid used to refer to shapes with exactly one set of parallel sides. I think shapes that Americans would call trapezoids may be called trapeziums elsewhere, and the definition of trapezium allows for shapes with two parallel sides, but the term trapezoid does not. | |
| Jan 25, 2021 at 15:08 | comment | added | T.J. Crowder | Definition of Trapezoid: "Any of several mechanisms designed to catch zoids. Originally the brand name Trap-a-Zoid™ but as with Kleenex™ the term now refers to the category of devices." (I'll see myself out...) | |
| Jan 25, 2021 at 14:57 | comment | added | Darrel Hoffman | And don't get started on "isosceles trapezoid", "acute vs. right vs. obtuse trapezoid", "tangental trapezoid", etc... | |
| S Jan 25, 2021 at 14:03 | history | suggested | Eric Duminil | CC BY-SA 4.0 |
Typo in title
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| Jan 25, 2021 at 13:31 | review | Suggested edits | |||
| S Jan 25, 2021 at 14:03 | |||||
| Jan 25, 2021 at 0:46 | comment | added | Flydog57 | Oops, "... each have two apples" (I can't edit a comment). In any case, the teacher insisted that I write the solution as "2 + 2 + 2 = 6" and that "2 x 3 = 6" was wrong because "you haven't learned multiplication yet". Ah, 3rd grade (back in the 1960s). | |
| Jan 24, 2021 at 22:57 | comment | added | Flydog57 | An important thing for Math Educators is that if one of your students comes up with either of these definitions, even if only one of them is in the book, the student is not wrong. When I was a young student, I often got in trouble for answering questions that were beyond the lesson plan (most egregiously, I got sent to the principal for answering: "Jane, Bob and Bill each have three apples, how many apples do they have together?" by saying "3 people each with 2 apples, 3 x 2 = 6". The teacher argued "you haven't learned multiplication yet", with me answering "well, obviously, I have" | |
| Jan 24, 2021 at 21:50 | history | became hot network question | |||
| Jan 24, 2021 at 14:48 | answer | added | user507 | timeline score: 21 | |
| Jan 24, 2021 at 14:45 | comment | added | mweiss | For historical context on the inclusive and exclusive definitions of "trapezoid", see my answer at matheducators.stackexchange.com/questions/13700/… | |
| Jan 24, 2021 at 14:41 | history | edited | J W |
Added tags
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| Jan 24, 2021 at 14:03 | answer | added | Carser | timeline score: 8 | |
| Jan 24, 2021 at 13:46 | history | asked | JTP - Apologise to Monica | CC BY-SA 4.0 |