Octahedron
Octahedron Facts
Notice these interesting things:
- It has 8 Faces
- Each face is an Equilateral Triangle
- It has 12 Edges
- It has 6 Vertices (corner points)
- and at each vertex 4 edges meet
- It is one of the Platonic Solids
images/polyhedra.js?mode=octahedron
Volume and Surface Area
Volume = (√2)/3 × (Edge Length)3
Surface Area = 2 × √3 × (Edge Length)2
It is called an octahedron because it is a polyhedron that has 8 (octa-) faces, (like an octopus has 8 tentacles)
When we have more than one octahedron they are called octahedra
When we say "octahedron" we often mean "regular octahedron" (in other words all faces are the same size and shape), but it doesn't have to be - this is also an octahedron, even though all faces are not the same. (But it may be better to call it a hexagonal prism).
8-Sided Dice? Yes! An octahedron that has 8 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.
| Make your own Octahedron, cut out the shape and glue it together. |
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1856, 1857, 1858, 1859