Beiträge zur Algebra und Geometrie Contributions to Algebra and Geometry Vol. 51, No. 1, pp. 111115 (2010) 

Spherical QuadranglesCatarina P. Avelino, A. M. d'Azevedo Breda and Altino F. SantosDepartment of Mathematics, UTAD, 5001  801 Vila Real, Portugal, email: cavelino@utad.pt; Department of Mathematics, University of Aveiro, 3810193 Aveiro, Portugal, email: ambreda@ua.pt; Department of Mathematics, UTAD, 5001  801 Vila Real, Portugal, email: afolgado@utad.ptAbstract: We introduce the notion of quasiwellcentered spherical quadrangle, or QWCSQ for short, describing a geometrical method to construct any QWCSQ. It is shown that any spherical quadrangle is congruent to a QWCSQ. We classify such quadrangles taking in account the relative position of the spherical moons containing their sides. This allows us to conclude that the class of all QWCSQ is a differentiable manifold of dimension five. Keywords: spherical geometry, applications of spherical trigonometry Full text of the article:
Electronic version published on: 27 Jan 2010. This page was last modified: 28 Jan 2013.
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