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Bibliographic Details
Main Authors: Minevich, Igor, Morton, Patrick
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2503.22073
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author Minevich, Igor
Morton, Patrick
author_facet Minevich, Igor
Morton, Patrick
contents If $ABC$ is a given triangle in the plane, $P$ is any point not on the extended sides of $ABC$ or its anticomplementary triangle, $Q$ is the complement of the isotomic conjugate of $P$ with respect to $ABC$, $DEF$ is the cevian triangle of $P$, and $D_0$ and $A_0$ are the midpoints of segments $BC$ and $EF$, respectively, a synthetic proof is given for the fact that the complete quadrilateral defined by the lines $AP, AQ, D_0Q, D_0A_0$ is perspective by a Euclidean half-turn to the similarly defined complete quadrilateral for the isotomic conjugate $P'$ of $P$ . This fact is used to define and prove the existence of a generalized circumcenter and generalized orthocenter for any such point $P$.
format Preprint
id arxiv_https___arxiv_org_abs_2503_22073
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A quadrilateral half-turn theorem
Minevich, Igor
Morton, Patrick
Algebraic Geometry
51A05
If $ABC$ is a given triangle in the plane, $P$ is any point not on the extended sides of $ABC$ or its anticomplementary triangle, $Q$ is the complement of the isotomic conjugate of $P$ with respect to $ABC$, $DEF$ is the cevian triangle of $P$, and $D_0$ and $A_0$ are the midpoints of segments $BC$ and $EF$, respectively, a synthetic proof is given for the fact that the complete quadrilateral defined by the lines $AP, AQ, D_0Q, D_0A_0$ is perspective by a Euclidean half-turn to the similarly defined complete quadrilateral for the isotomic conjugate $P'$ of $P$ . This fact is used to define and prove the existence of a generalized circumcenter and generalized orthocenter for any such point $P$.
title A quadrilateral half-turn theorem
topic Algebraic Geometry
51A05
url https://arxiv.org/abs/2503.22073