Sentence Examples

  • Nevertheless, holding that every dimension has a principle of its own, he rejected the derivation of the elemental solids - pyramid, octahedron, icosahedron and cube - from triangular surfaces, and in so far approximated to atomism.
  • The names of these five solids are: (r) the tetrahedron, enclosed by four equilateral triangles; (2) the cube or hexahedron, enclosed by 6 squares; (3) the octahedron, enclosed by 8 equilateral triangles; (4) the dodecahedron, enclosed by 12 pentagons; (5) the icosahedron, enclosed by 20 equilateral triangles.
  • The first three were certainly known to the Egyptians; and it is probable that the icosahedron and dodecahedron were added by the Greeks.
  • The equilateral triangle is the basis of the tetrahedron, octahedron and icosahedron.'