6-3B Regular Polyhedrons What is a regular polyhedron? What are Platonic solids? What are the names of the Platonic solids?

Regular Polyhedron Congruent edges and faces Faces that are regular polygons An equal number of edges meeting at each vertex A convex regular polyhedron is one with no “dents”.

Platonic Solids Platonic Solids are five convex regular polyhedrons discovered over 2,000 years ago and named in honor of the Greek philosopher Plato. They are: Regular tetrahedron Regular hexahedron Regular octahedron Regular dodecahedron Regular icosahedron

Regular tetrahedron

Regular hexahedron

Regular octahedron

Regular dodecahedron

Regular icosahedron

Purely Platonic Name Type of face # of faces # of edges # of vertices Tetrahedron Triangle 4 6 Hexahedron Square 6 12 8 Octahedron Triangle 8 12 6 Dodecahedron Pentagon 12 20 30 Icosahedron Triangle 20 12 30

Name the convex regular polyhedron that has the given set of characteristics Five equilateral triangular faces meet at each vertex Square faces Three equilateral triangular faces meet at each vertex Regular icosahedron Regular hexahedron Regular tetrahedron

Do platonic solids occur in nature? Chrome alum octahedrons Salt hexahedrons Sugar

Concave regular polyhedrons Great Icosahedron Great Stellated Dodecahedron Small Stellated Dodecahedron

Uniform Polyhedra

What is a regular polyhedron? Congruent edges and faces, faces that are regular polygons, and an equal number of edges meeting at each vertex. What are Platonic solids? Platonic Solids are five convex regular polyhedrons. What are the names of the Platonic solids? Tetrahedron, hexahedron, octahedron, dodecahedron, icosahedron.

Assignment 6-3B Page 450, 1-10,23-24