A triangle is a polygon. It is a closed 3-sided shape made up of straight lines. The ‘tri-’ part of the word triangle means three. A triangle has 3 sides and 3 angles. Interior angles are the angles ...

Named for Plato, who theorized that the classical elements were made of these regular polyhedrons, three of the Platonic solids are composed of equilateral triangles: the tetrahedron, octahedron, and ...

About a decade ago Tonan Kamata, now a mathematician at the Japan Advanced Institute of Science and Technology (JAIST), stood mesmerized in front of a math museum’s origamilike exhibit. It featured a ...

https://doi.org/10.4169/amer.math.monthly.124.1.70 https://www.jstor.org/stable/10.4169/amer.math.monthly.124.1.70 We provide a geometric explanation, based on ...