A new class of monohedral pentagonal spherical tilings with GeoGebra

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Portugaliae Mathematica

Volume 74, Issue 3, 2017, pp. 257–266 DOI: 10.4171/PM/2006 Published online: 2018-02-08 A new class of monohedral pentagonal spherical tilings with GeoGebra Ana M. d'Azevedo Breda[1] and José M. Dos Santos Dos Santos[2] (1) Universidade de Aveiro, Portugal (2) Universidade Aberta, Lisboa, Portugal By a monohedral spherical tiling we mean a decomposition of the sphere by geodesic congruent polygons. Here, making use of GeoGebra, a well known free interactive mathematics software, we show how to generate new classes of monohedral non-convex triangular and new non-convex pentagonal spherical tilings, changing the side gluing rules of the regular spherical tetrahedral tiling, by means of a local action of particular subgroups of spherical isometries. In both cases each face has $\pi$ as area measure. In relation to the new class of pentagonal tilings, we describe some of their properties and show the existence, in a special case, of an associated dihedral triangular spherical tiling, that is, a tiling composed by two sets of congruent triangles. These classes of spherical tilings have emerged as a result of an interative construction process, only possible by the use of newly produced GeoGebra tools and the dynamic interaction capabilities of this software. Keywords: Spherical geometry, spherical tilings, GeoGebra d'Azevedo Breda Ana M., Dos Santos Dos Santos José: A new class of monohedral pentagonal spherical tilings with GeoGebra. Port. Math. 74 (2017), 257-266. doi: 10.4171/PM/2006 https://www.ems-ph.org/journals/show_abstract.php?issn=0032-5155&vol=74&iss=3&rank=7