Cube (original) (raw)

A cube (or hexahedron) is a Platonic solid composed of six square faces, with three meeting at each vertex. The cube is a special kind of square prism and of triangular trapezohedron, and is dual to the octahedron. Canonical coordinates for the vertices of a cube centered at the origin are (±1,±1,±1), while the interior of the same consists of all points (x0, x1, x2) with -1 < xi < 1.

A cube can be inscribed in a dodecahedron so that each vertex of the cube is a vertex of the dodecahedron and each edge is a diagonal of one of the dodecahedron's faces; taking all such cubes gives rise to the regular compound of five cubes. The compound of two tetrahedra is made from the cube in like fashion. The cube is unique among the Platonic solids for being able to tile space regularly, and finds many uses because of this. For instance, sugar is usually cut into cubes, and the familiar six-sided die is cube shaped.

In an _n_-dimensional space the analog of the figure is called _n_-dimensional cube, or simply cube, if it doesn't lead to a confusion.

In the four-dimensional geometry, the analogue of a cube has a special name - a tesseract.

In arithmetic and algebra, the cube of an entity x is its third power - the result of multiplying it by itself two times: _x_3 = x × x × x. This is the also the volume of a geometric cube of side x, giving rise to the name.

The inverse operation of finding the real number that, multiplied with itself two times, becomes x is called extracting the cube root of x. It determines the side of the cube of a given volume. It is also x raised to the power of one-third.

See also: Dice, Time Cube (Gene Ray), Unit cube