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 Discussion: All Tools in Geometry on Computer Topic: geom construction software with compass -> arcs, not circles

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 Subject: RE: geom construction software with compass -> arcs, not circles Author: jdad Date: Sep 23 2011
On Sep 23 2011, PeterA wrote:
> You can create an arc like you want in Sketchpad. I'm assuming that
> it would solve your problem if you could draw an arc with center P,
> passing through Q, and extending t = 10 degrees to either side of Q.
> To do this, use the Transform menu.
(1) Select P and do Transform >
> Mark Center
(2) Select Q and do Transform > Rotate 10 degrees about
> center P (creating R)
(3) Select Q and do Transform > Rotate -10
> degrees about center P (creating S)
(4) Select R, Q, and S and then
> Construct > Arc Through 3 Points

You can make a tool that will do
> this. Of course, you can replace 10 degrees by whatever you want,
> possibly even introducing a user-settable parameter. Please let us
> know if this works for you.

Thanks for the tip on transforms.  This worked to create an arc tool, but I'm
not sure how to fix the distance so I can use it in finding a midpoint, for
instance.

I followed steps 1-4, selected the objects, and clicked "create new tool."
Now if I use that tool, I can't specify the radius.  The only givens, per script
view, are point A and point B.  If I'm finding a midpoint of AC, after I create
an arc centered at A and through B (where B lies on AC), I need to create
another arc centered at C with radius AB that goes through another point D on
AC.

Is there a way to programatically create scripts in GSP?  (I.e. not using the
GUI).  I'm looking at Geogebra more and the ability to program looks like it
might be useful.