Timeline for How to give my students a straightedge instead of a ruler
Current License: CC BY-SA 4.0
35 events
| when toggle format | what | by | license | comment | |
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| Sep 4 at 15:24 | answer | added | easy fix | timeline score: -1 | |
| Aug 22, 2023 at 18:28 | comment | added | Ari Brodsky | What does "ETA" mean? | |
| Oct 27, 2019 at 20:38 | history | edited | Matthew Daly | CC BY-SA 4.0 |
added new update reviewing the unit.
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| Sep 17, 2019 at 14:56 | answer | added | Doktor J | timeline score: 0 | |
| Sep 17, 2019 at 12:30 | comment | added | Chris Cunningham | I deleted a significant number of comments here that were mini-answers or "Me too!" comments. Please continue to flag comments that aren't working as intended. | |
| Sep 16, 2019 at 23:45 | answer | added | dmckee --- ex-moderator kitten | timeline score: 0 | |
| Sep 16, 2019 at 22:07 | comment | added | GuilleOjeda | Note that the given example and other problems solvable by finding the not-so-exact point between two points can be cheated using a piece of paper: you set the close-to-straight edge of the paper connecting D and E, make a mark on the paper for each point, fold the paper in half with both marks approximately matching position, mark the folded edge of the paper, unfold it and reset it on DE, and you have an approximate mark for F. And there are other ways to approximate the midpoint between two points, for example with a pencil and a straightedge you can write on (like a craft stick) | |
| Sep 16, 2019 at 20:50 | comment | added | Matthew Daly | @Acccumulation I agree, which is why I don't even want students to have the resources to be tempted down a false path like this erroneous construction. | |
| Sep 16, 2019 at 20:37 | comment | added | Acccumulation | @MatthewDaly That's not "constructing" F, and it depends on the distance being an even integer number of ticks, and on having infinite precision. | |
| Sep 16, 2019 at 20:01 | comment | added | Matthew Daly | @Acccumulation Put the zero end of the ruler at D, measure the distance at E, and mark at F at half of whatever distance you find. | |
| Sep 16, 2019 at 18:22 | comment | added | Acccumulation | "Then, using the ruler to measure DE, construct F as the midpoint." That doesn't make sense. | |
| Sep 16, 2019 at 17:20 | review | Close votes | |||
| Sep 17, 2019 at 2:24 | |||||
| Sep 16, 2019 at 16:27 | comment | added | dbmag9 | In my experience, students who fake their constructions never get them as accurate as when it's done properly. If you give them the starting lines (CAB in your example) then you can check very easily with an overlay and the small deviations that result from using a ruler become very obvious. | |
| Sep 16, 2019 at 15:41 | answer | added | user12716 | timeline score: 1 | |
| Sep 16, 2019 at 12:50 | answer | added | Chris H | timeline score: 1 | |
| Sep 16, 2019 at 12:28 | answer | added | user12713 | timeline score: 1 | |
| Sep 15, 2019 at 16:27 | comment | added | Matthew Daly | @user1527 I would also add that an arbitrary angle can be trisected using a compass and a ruler, and that has been understood through history as "cheating" as strict constructions go. | |
| Sep 15, 2019 at 12:51 | comment | added | Konrad Rudolph | Funny, your example is the exact exam question which I “solved” using a ruler in middle school geometry, and for which I got in trouble when fighting (rather violently) the teacher's “unjust” docking of points. So +1, very good question. | |
| Sep 15, 2019 at 9:14 | history | edited | Matthew Daly | CC BY-SA 4.0 |
fixed typo
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| Sep 15, 2019 at 4:07 | answer | added | Rodrigo A. Pérez | timeline score: 4 | |
| Sep 14, 2019 at 23:03 | answer | added | user2813274 | timeline score: 2 | |
| Sep 14, 2019 at 20:50 | history | edited | JTP - Apologise to Monica | CC BY-SA 4.0 |
deleted 1 character in body
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| Sep 14, 2019 at 19:57 | answer | added | Chris Barry | timeline score: 6 | |
| Sep 14, 2019 at 16:30 | answer | added | MTA | timeline score: 17 | |
| Sep 14, 2019 at 6:07 | history | edited | Matthew Daly | CC BY-SA 4.0 |
correction in the first sentence.
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| Sep 14, 2019 at 0:55 | history | became hot network question | |||
| Sep 13, 2019 at 23:46 | history | edited | Matthew Daly | CC BY-SA 4.0 |
added my sollution
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| Sep 13, 2019 at 23:43 | vote | accept | Matthew Daly | ||
| Sep 13, 2019 at 20:41 | comment | added | Matthew Daly | @RustyCore LOL, Unfortunately, I also need actual rulers from time to time too. But buying super-cheap rulers and then defacing them is an intriguing idea! | |
| Sep 13, 2019 at 20:37 | history | edited | Matthew Daly | CC BY-SA 4.0 |
added example
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| Sep 13, 2019 at 17:56 | comment | added | Rusty Core | On the rulers that I have, the markings come off just from normal usage, cheap junk. But fortunate to you, just sand the markings off, should not take long. Ask your students to do that — some vocational skills while inhaling microplastics, yay. | |
| Sep 13, 2019 at 17:39 | answer | added | Nick C | timeline score: 1 | |
| Sep 13, 2019 at 17:29 | answer | added | Xander Henderson♦ | timeline score: 18 | |
| Sep 13, 2019 at 17:15 | answer | added | Jasper | timeline score: 11 | |
| Sep 13, 2019 at 16:46 | history | asked | Matthew Daly | CC BY-SA 4.0 |