Beitr\ EMIS ELibM Electronic Journals Beiträge zur Algebra und Geometrie
Contributions to Algebra and Geometry
Vol. 44, No. 2, pp. 339-349 (2003)

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Well centered spherical quadrangles

Ana M. d'Azevedo Breda and Altino F. Santos

Department of Mathematics, University of Aveiro, 3810 - 193 Aveiro, Portugal, e-mail:; Department of Mathematics, U.T.A.D., 5001 - 911 Vila Real, Portugal, e-mail:

Abstract: We introduce the notion of a well centered spherical quadrangle or WCSQ for short, describing a geometrical method to construct any WCSQ. We shall show that any spherical quadrangle with congruent opposite internal angles is congruent to a WCSQ. We may classify them taking in account the relative position of the spherical moons containing its sides. Proposition 3 describes the relations between well centered spherical moons and WCSQ which allow the refereed classification.

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Electronic version published on: 1 Aug 2003. This page was last modified: 4 May 2006.

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