A distance property of the Feuerbach point and its extension - Sándor N. Kiss We prove that among the distances from the inner Feuerbach point of...
Regular polygons and the golden section - Djura Paunić and Paul Yiu Given an isosceles triangle and its circumcircle, we construct a chord...
Some golden sections in the equilateral and right isosceles triangles - Dao Thanh Oai Associated with the equilateral triangle and the right...
Locus of centroids of similar inscribed triangles - Francisco Javier García Capitán We study the locus of the centroids of families of similar...
Some collinearities in the heptagonal triangle - Abdilkadir Altintaş With the methods of barycentric coordinates, we establish several...
Cevian projections of inscribed triangles and generalized Wallace lines - Gotthard Weise Let Delta = ABC be a reference triangle and Delta' =...
Area of the orthic quadrilaterals of a convex cyclic orthodiagonal quadrilateral - Grégoire Nicollier Among all orthic quadrilaterals inscribed...
Regular polytopic distances - Poo-Sung Park Let M be an n-dimensional regular polytope of simplices, hypercubes, or orthoplexes and r be the...
On the diagonal and inscribed pentagons of a pentagon - Paris Pamfilos In this article we study two projective maps f and g, naturally associated...
Septic equations are solvable by 2-fold origami - Joachim König and Dmitri Nedrenco In this paper we prove that a generic polynomial equation of...
Some loci in the animation of a Sangaku diagram - Junghyun Lee, Minyoung Hwang, and Cheolwon Bae In a symmetric partition of a regular n-gon into...
A proof of the butterfly theorem using Ceva's theorem - Cesare Donolato A proof is given of the butterfly theorem by using a simple auxiliary...
A recursive formula for the circumradius of the n-simplex - Kenta Kobayashi We present a recursive formula which gives the circumradius of the...
Isogonal conjugacy through a fixed point theorem - Sándor N. Kiss and ZoltánKovács For all point X in the plane set the affine combination of...
A special case of Poncelet's problem - Arthur Holshouser, Stanislav Molchanov, and Harold Reiter A special case of Poncelet's Theorem states that...
Applying Poncelet's theorem to the pentagon and the pentagonal star - Arthur Holshouser, Stanislav Molchanov, and Harold Reiter A special case of...
A quadrilateral half-turn theorem - Igor Minevich and Patrick Morton If ABC is a given triangle in the plane, P is any point not on the extended...
Ascending lines in the hyperbolic plane - Dieter Ruoff On the basis of the familiar proportionality theorems a line in the Euclidean plane, which...
Golden sections of triangle centers in the golden triangles - Emmanuel A. J. García and Paul Yiu A golden triangle is one whose vertices are...
The triangle construction - Paris Pamfilos We study the problem of constructing a triangle from the data {α, b-c, t_A}, t_A being the length of...
