Κυριακή 20 Οκτωβρίου 2019

HYACINTHOS 8088

Dear friends,
Let A1,B1,C1 be the second intersections of AI,BI,CI
with three excircles.
Then
1.Ttriangles A1B1C1 and medial triangle of triangle ABC
are perspective at point
P1(sin(B/2)+sin(C/2):sin(C/2)+sin(A/2):sin(A/2)+sin(B/2))
2.Triangles A1B1C1 and intouch triangle of triangle ABC
are perspective at point
P2([1/(s-a)]*[sin(B/2)+sin(C/2)]*sin(A/2):
[1/(s-b)]*[sin(C/2)+sin(A/2)]*sin(B/2):
[1/(s-c)]*[sin(A/2)+sin(B/2)]*sin(C/2)).
The coordinate are barycentric.
P1,X(174) and G are collinear.
As I could check these points are not in ETC.

Best regards
Milorad R.Stevanovic
 
 

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