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18 votes
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How to give my students a straightedge instead of a ruler

I have lots of ideas, which, it turns out, aren't going to fit into a comment. If you don't need something too long, but want something that is pretty uniform and consistent, popsicle sticks (also ...
Xander Henderson's user avatar
  • 8,225
17 votes

How to give my students a straightedge instead of a ruler

A cheap Venetian blind with thin plastic slats can be cut up with ordinary scissors and will yield many straightedges of any length you choose. The slight bow in the blade will flatten out when ...
MTA's user avatar
  • 271
11 votes

How to give my students a straightedge instead of a ruler

Try shopping for a "paint guide". These products have: a straight plastic or metal edge a grippable portion that is not on the edge no ruler-like markings low prices. Drafting triangles also have ...
Jasper's user avatar
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6 votes

How to give my students a straightedge instead of a ruler

Take an ordinary piece of paper and fold it. This must be the simplest way to produce an edge that is absolutely straight. A folded paper can be used to verify the straightness of a ruler, which ...
Chris Barry's user avatar
5 votes

Is there online geometric construction software that models physical constructions?

Have you checked out Math Open Reference? The site has animations that demonstrate how to do the constructions, in the style that you indicated. It won't let students DO the construction online; ...
Carmine D'Agosto's user avatar
4 votes

Is there online geometric construction software that models physical constructions?

This looks promising but it is not free: mathspad.co.uk.       You can experiment with the tools without creating (or paying for) an account:      
Joseph O'Rourke's user avatar
4 votes

How to give my students a straightedge instead of a ruler

I hope you like this one... String
Rodrigo A. Pérez's user avatar
4 votes

Is there online geometric construction software that models physical constructions?

Are you aware you can choose not to show objects or labels with Geogebra? You can draw arcs, but at first the bounding points will be shown too, but you can hide them afterwards, as in this example:
Dominique's user avatar
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4 votes

Should the construction of triangles be taught?

I am a strong advocate for teaching constructions. At least when it comes to high school geometry. My experience in teaching geometry to freshmen and sophomore high school students has shown me how ...
A.Ellett's user avatar
  • 390
3 votes

Should the construction of triangles be taught?

I suggest that emphasizing plane geometry problems and their solutions could be more effective than a systematic introduction to constructive geometry. For example: Alexander Shen. Geometry in ...
Joseph O'Rourke's user avatar
3 votes

Should the construction of triangles be taught?

I've recently committed, in my college algebra classes, to presenting proofs for as many or all topics that I possibly can. This has made me much more aware of how often basic geometry constructions (...
Daniel R. Collins's user avatar
2 votes

Is there online geometric construction software that models physical constructions?

I think https://www.robocompass.com/ fits the bill... if you are ok with something code-driven, which for me is just an amazing bonus for my students and for exposition. So, the way in which ...
Brad Franklin's user avatar
2 votes

How to give my students a straightedge instead of a ruler

Stock metal comes to mind if you want something slightly better than plastic/paper type things - in the u.s for example this can be acquired at hardware stores and cut to size relatively easily, here ...
user2813274's user avatar
2 votes

How to give my students a straightedge instead of a ruler

Take a first step by forbidding straightedges also. This will make them understand that every construction possible with straightedge and compass is also constructible with compass alone (Mohr-...
user12713's user avatar
1 vote

Is there online geometric construction software that models physical constructions?

you can consider using https://cabricloud.com/cabriexpress/secondary/ There is an on screen compass, protractor, ruler and set square.
Munah's user avatar
  • 11
1 vote

How to give my students a straightedge instead of a ruler

Tongue Depressor - They are six inches long and you can get a pack of 100 on amazon for about five dollars. You can also get them at your local Walmart or Hobby Lobby.
user12716's user avatar
1 vote

How to give my students a straightedge instead of a ruler

Aluminium carpet joining strips are another hardware store option. They make nice straight edges for use with craft knives and would also serve well here. They're a better shape than cheap metal bar ...
Chris H's user avatar
  • 261
1 vote

How to give my students a straightedge instead of a ruler

You could use a beam compass and only let them use one side of the compass as the straightedge.
Nick C's user avatar
  • 9,639
1 vote

Should the construction of triangles be taught?

I strongly believe in teaching construction problems. They can be used to stimulate lively discussions in the class. For example, see the several construction problems in Geometric Transformations, ...
Muralidharan's user avatar

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