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Re: Three halfcircles
Posted:
Sep 6, 2011 8:51 PM


Avni Pllana wrote:
> Let D1, E1, F1 be the projections on the xyplane of > the respective touching points of the halfcircles > with the tangent plane. The lines DD1, EE1, FF1 are > concurrent at the symmedian point X(6) of triangle > DEF. Furthermore, the intersection of the tangent > plane with the xyplane coincides with the tripolar > line of the symmedian point.
I have verified independently that DD1, EE1, FF1 are concurrent in the general case. You have gone quite a bit beyond in identifying the intersection point and the trace of the tangent plane. Good job!
Rouben



