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X(6326), X(34464), X(72946), X(72947), X(72948), X(72949), X(72950), X(72951), X(72952), X(72953), X(72954)

excenters

(contributed by Peter Moses, 2026-09-03)

A reference : A poristic system of triangles, a thesis by Rufus Crane, Ohio State University, 1925

Q199 is the locus of the vertices of triangles sharing the same incircle and nine-point circle as ABC. The locus of their excenters is Q200.

Q200 is a bicircular nodal quartic with node X(6326) = reflection of X(80) in X(119) and singular focus X(5). It is symmetric in the line (L) passing through X(1), X(5), X(80), etc.

Q200 is the excentral polar circle inverse of Q199.