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Topic: inscribing a circle
Replies: 4   Last Post: Feb 15, 2000 6:08 PM

 Messages: [ Previous | Next ]
 Jon Roberts Posts: 47 Registered: 12/6/04
Re: inscribing a circle
Posted: Dec 20, 1999 9:51 PM

Hi Hakan,

I think that you need to _construct_ the circle after you find its centre rather
than _draw_ it .
To do this,
(1) draw a line through the center (intersection of the angle bisectors) which
is perpendicular to one of the sides of the triangle.
(2) construct a point at the intersection of the perpendicular and the side
(3) construct a circle with center point at the angle bisectors' intersection
and as the radius point use the point constructed in (2).
This should give you the in-circle, which touches the triangle at 3 points.

Regards,

Jon Roberts

Hakan Aras wrote:

> When I draw an inscribed circle in any triangle using the intersection point
> of the angle bisectors as the center point of that circle, Cabri and
> Sketchpad claim that they have no intersection point(s) although visually
> the circle seems to touch the triangle at three points. When I enlarge the
> circle a little, this time those sofware claim that it touches the triangle
> at six points( two intersection points for each vertex).There is no other
> case between these.As far as i know from my experiences.
> But theoretically every inscribed circle is drawn by using the intersection
> point of the angle bisectors as the center point of that circle.
> So does it mean that these software are deficient to do this task?

Date Subject Author
12/20/99 Hakan Aras
12/20/99 Jon Roberts
12/22/99 Keith Dean
12/22/99 Konstantin Shemyak
2/15/00 Ulrich Kortenkamp