[SCIENCE CORNER] MATHEMATICS CLASS ROOM

There are only five solids that can be called platonic solids – the tetrahedron, the hexahedron or cube, the octahedron, the dodecahedron and the icosahedron. They are also called regular geometric solids or polyhedra and are 3D in shape. Each face of a Platonic Solid is the same regular sized polygon. The name of each shape is derived from the number of its faces – 4 (tetrahedron), 6 (hexahedron), 8 (octahedron), 12 (dodecahedron) and 20 (icosahedron). For each Platonic Solid, the same numbers of polygons or faces meet at each vertex or corner. Each Platonic Solid has a dual polyhedron.

Definitions:

♦ A polyhedra solid must have all flat faces (eg. Platonic Solids, prisms and pyramids), whilst a non-polyhedra solid has a least one of its surfaces that is not flat (eg. cylinder, sphere or cone).

♦ Regular means all angles are of equal measure, all faces are congruent shapes or equal in every aspect, and all edges are of equal length.

♦ 3D means that shape has width, depth and height.

♦ A polygon is a closed shape in a plane figure with at least five straight edges.

♦ A dual is a Platonic Solid that fits inside another Platonic Solid and connects to the mid-point of each face.