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Discussion: All Topics in Geometry
Topic: Smartboard and Geometric Constructions


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Subject:   RE: Smartboard and Geometric Constructions
Author: Don Link
Date: Aug 31 2006
I believe you can approach the constructions by using the line segment tool for
the straight edge and a circle item from the gallery for the compass.  

For example, to construct a line perpendicular to a given line at a given point
on the given line, you can follow this procedure:

1) Draw a line segment.
2) Use the pen to mark a point on the line (e.g., in red)
3) Use the circle item in the Math/Shapes/Area gallery.  It shows the center
point, and you can resize it as needed.  Place its center on the marked point
from step 2, and use the red pen again to mark its two intersection points on
the line.
4) Duplicate the circle (ctrl-D) and enlarge it.
5) Center the enlarged circle on one of the marked intersection points from step
3.
6) Duplicate this enlarged circle and center it on the other marked intersection
point.
7) Using the line tool, start at the top-most intersection of the two larger
circles and drag the line down through the other intersection point of the two
larger circles.

This last line segment is perpendicular to the original line and passes through
the given point.

I know this is overkill, but I wanted to be very specific.  This approach should
allow you to do allow geometric constructions that use straight edge and
compass.

Note also that with the Notebook's oval tool, if you hold down the Shift key
when you drag the oval, you will get a circle.

Hope this helps,
Don Link

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