Online Geometry: Equilateral Triangles, Theorems and Problems - Page 5

Hexagon and Lissajous Art  

Index, Platonic Solids, Interactive animation, Tetrahedron in the cube, Archimedes and the Rhombicuboctahedron with animation, In the News, Video: How to make platonic solids with gum drops and tooth picks

Geometry and Cultures Gold Tumi.

Triangles and Lissajous Art  

Equilic Quadrilateral.
 

Napoleon's Theorem. A purely geometric proof. It uses the Fermat point to prove Napoleon without transformations.
 

Morley's Theorem. Introduction with animation. Triangle + Trisectors = Equilateral triangle.

Morley's Theorem Puzzle: 22 pieces of polygons.

Langley's Problem Adventitious angles. 20° isosceles triangle with animation.
 

Kurschak's Tile and Theorem. Jozsef Kurschak (Hungary, 1864-1933) A square, with equilateral triangles. An elegant and a purely geometric way of finding the area of a regular dodecagon.