Discussion:  All Topics on Computer 
Topic:  Proof of Pythagoras Theorem 
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Subject:  RE: Proof of Pythagoras Theorem 
Author:  NateB 
Date:  Apr 2 2008 
the animation buttons. You can tell a point to move to a different point and it
stays there. I usually make a few buttons and control the movement as a
presentation.
As far as the object disappearing and being replaced by a differently defined
but visually identical object, you can make a presentation that moves A and
hides A and shows B. This allows you to introduce independent points part way
through a complicated construction and they have the freedom of independence
without the arbitrary location. I have used this technique on a Stats sketch to
show points apparently moving through two tranformations, although you really
see a couple of different sets of points. The file and others can be found on
this page:
http://nateburchell.googlepages.com/gsp_files.html
Finally, you can make a point go around a corner by using the movement buttons.
If you want point A to go along a straight line to point B where it will change
directions and continue to point C, create two buttons: Move A>B and Move
A>C. Now make a presentation of the buttons and as long as the movements
happen sequentially (not simultaneously) then the visual effect will be what you
are describing.
You can create a point on a polygon. Click (in order) the points that define a
polygon. Construct a polygon interior. With the polygon selected, Construct a
point on the polygon. This point can be told to go to a different point on the
polygon, and it seems to take the shortest route.
Hope this helps.
Nate
On Apr 1 2008, Davem wrote:
> I once saw a proof of Pythagoras' Theorem created with Cabri
> Geometry which involved shears and translations. I'm trying to
> setup a similar demonstration in Sketchpad, but I'm meeting a few
> stumbling blocks and wonder if anyone can help.
1) Sometimes I
> want to use an animation button to move a point (and hence an
> object, e.g. a square) along a line, and then have it stop at the
> end. But in GSP it always returns to its starting point at the end
> of the animation. Anyway to overcome this/work around this?
2)
> I'd like to make an object disappear then have another (apparently)
> identical object reappear in the same place. At present the change
> is very obvious. Any suggestions how to deal with this?
3) Is
> there anyway I can make a point go around a corner? I'm remembering
> that in Cabri I could define a point as being on the sides of a
> polygon, but is there anyway to achieve this in Sketchpad?
Those
> are the main stumbling blocks I'm up against at present. Any help
> would be much appreciated.
 
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