If the pyramid has a triangular sides then truncate each vertex (cut off a small pyramid shape from the vertices).
If the pyramid has a quadrilateral base then truncate 3 vertices.
If the pyramid has a pentagonal base then truncate 2 vertices.
If the pyramid has a hexagonal base then truncate 1 vertex.
If the pyramid has a heptagonal base then it is already an octahedron.
If the pyramid has an base with 8 or more vertices then slice off the section formed by joining the apex and two vertices from the base which are six apart. This makes the base heptagonal and therefore the shape is an octahedron.
Start with an octahedron in the form of a quadrilateral based dipyramid a regular octahedron is a special case of this). This shape has six vertices - chop these off so as to remove a quadrilateral based pyramid. You will be left with a truncated octahedron. It is an octahedron which has been truncated (shortened) by cutting off its extremities.
It can be but need not be. A heptagon-based pyramid is an octahedron. However, the term is often used for the Platonic solid bounded by eight equilateral triangles - in the form of two square based pyramids stuck together base-to-base.
The general formula for any type of pyramid - as well as for cones - is (1/3)Bh, where "B" is the base area, and "h" is the perpendicular height.
An octahedron is the name for a non-specific shape. It could be a di-rectangular pyramid with 6 vertices - this is like two rectangular [or square] based pyramids stuck together base-to-base. Or it could be a heptagonal pyramid, in which case it has 8 vertices. Or it could be a hexagonal prism, in which case it has 12 vertices. There are other octahedraons.
Octahedron. It is two square pyramids that share a base (Imagine a pyramid from Egypt, flip it upside down, and stick that to the bottom of the original pyramid).
A regular octahedron and a heptagonal pyramid.A regular octahedron and a heptagonal pyramid.A regular octahedron and a heptagonal pyramid.A regular octahedron and a heptagonal pyramid.
No, it is not.
Not necessarily. A heptagon-based pyramid is an octahedron and it has no parallel faces.
Start with an octahedron in the form of a quadrilateral based dipyramid a regular octahedron is a special case of this). This shape has six vertices - chop these off so as to remove a quadrilateral based pyramid. You will be left with a truncated octahedron. It is an octahedron which has been truncated (shortened) by cutting off its extremities.
An octahedron is a polyhedron with eight faces. A regular octahedron can be composed of eight equilateral triangles, four forming each half, and meeting in the middle at a square. Imagine a pyramid, with a square base. Rising up from each edge is an equilateral triangle that meets the other four triangles at the apex. Now, turn the pyramid over and add four more triangles to the other side the same way. You now have an octahedron. For more information, and a rotating picture, please see the related link below.
Here are three; cube, octahedron, hexagonal pyramid.
An octahedron
It can be but need not be. A heptagon-based pyramid is an octahedron. However, the term is often used for the Platonic solid bounded by eight equilateral triangles - in the form of two square based pyramids stuck together base-to-base.
The platonic solids are: a tetrahedron, a cube, an octahedron, dodecahedron and icosahedron. A pyramid has a base with triangles attached to it with a common vertex. The platonic solid that is a pyramid is a tetrahedron (a triangular based pyramid).
An octahedron is the name for a non-specific shape. It could, as described above, be a di-rectangular pyramid with 6 vertices. Or it could be a heptagonal pyramid, in which case it has 8 vertices. Or it could be a hexagonal prism, in which case it has 12 vertices. There are other octahedraons.
You start with a quadrilateral based bipyramid, which has six vertices. At each vertex, remove the tip in the form of a quadrilateral based pyramid. You will be left with a truncated octahedron.
A tetrahedron, a triangle based pyramid, an octahedron, an icosahedron plus many more.