Volume 18 2018
FORUM GEOMETRICORUM A Journal on Classical Euclidean Geometry and Related Areas published by Department of Mathematical Sciences Florida Atlantic University FORUM GEOM Volume 18 2018 http://forumgeom.fau.edu ISSN 1534-1188 Editorial Board Advisors: John H. Conway Princeton, New Jersey, USA Julio Gonzalez Cabillon Montevideo, Uruguay Richard Guy Calgary, Alberta, Canada Clark Kimberling Evansville, Indiana, USA Kee Yuen Lam Vancouver, British Columbia, Canada Tsit Yuen Lam Berkeley, California, USA Fred Richman Boca Raton, Florida, USA Editor-in-chief: Paul Yiu Boca Raton, Florida, USA Editors: Eisso J. Atzema Orono, Maine, USA Nikolaos Dergiades Thessaloniki, Greece Roland Eddy St. John’s, Newfoundland, Canada Jean-Pierre Ehrmann Paris, France Chris Fisher Regina, Saskatchewan, Canada Rudolf Fritsch Munich, Germany Bernard Gibert St Etiene, France Antreas P. Hatzipolakis Athens, Greece Michael Lambrou Crete, Greece Floor van Lamoen Goes, Netherlands Fred Pui Fai Leung Singapore, Singapore Daniel B. Shapiro Columbus, Ohio, USA Man Keung Siu Hong Kong, China Peter Woo La Mirada, California, USA Li Zhou Winter Haven, Florida, USA Technical Editors: Yuandan Lin Boca Raton, Florida, USA Aaron Meyerowitz Boca Raton, Florida, USA Xiao-Dong Zhang Boca Raton, Florida, USA Consultants: Frederick Hoffman Boca Raton, Floirda, USA Stephen Locke Boca Raton, Florida, USA Heinrich Niederhausen Boca Raton, Florida, USA Table of Contents Stefan Liebscher and Dierck-E. Liebscher, The relativity of conics and circles,1 Carl Eberhart, Revisiting the quadrisection problem of Jacob Bernoulli,7 C. E. Garza-Hume, Maricarmen C. Jorge, and Arturo Olvera, Areas and shapes of planar irregular polygons,17 √ Samuel G. Moreno and Esther M. Garc´ıa–Caballero, Irrationality of 2:Yet another visual proof,37 Manfred Pietsch, Two hinged regular n-sided polygons, 39–42 Hiroshi Okumura, A remark on the arbelos and the regular star polygon,43 Lubomir P.
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