Dodecahedron
A 3D shape with 12 flat faces.
images/polyhedra.js?mode=dodecahedron
Dodecahedron Facts
Notice these interesting things:
- It has 12 faces
- It has 30 edges
- It has 20 vertices (corner points)
When it is regular:
- Each face is a pentagon (5 edges)
- At each vertex 3 edges meet
- It is one of the Platonic Solids
Volume and Surface Area
Surface Area =3 × √(25 + 10√5) × (Edge Length)2
Volume =(15 + 7√5) / 4 × (Edge Length)3
It is called a dodecahedron because it is a polyhedron that has 12 faces (from Greek dodeca- meaning 12).
When we have more than one dodecahedron they are called dodecahedra
When we say "dodecahedron" we often mean "regular dodecahedron" (in other words all faces are the same size and shape), but it doesn't have to be - this is also a dodecahedron, even though all faces are not the same.
12-Sided Dice? Yes! A dodecahedron which has 12 equal faces has an equal chance of landing on any face.
In fact, you can make fair dice out of all of the Platonic Solids.
Example: Dodecahedron in Art and Architecture
The dodecahedron is often used in art and architectural design to create visually striking structures.
| Make your own Dodecahedron, cut out the shape and glue it together. |
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1848, 1849, 1850, 1851