Geometric Name of Object - Rectangular Pyramid

[Ryan.C]

Hi All,

I'm wondering what I would describe as a 'rectangular pyramid' with a equal slope on all sides is actually called? The fact it has an equal slope on all sides means that it has a line for it's top apex not a point.

The equal slope is not actually a necessity for the object I'm chasing a name for, its just the easiest way for me to describe a rectangular pyramid that culminates in a line for an apex.

All definitions I can find for 'pyramid' have a point for an apex, therefore I can only assume that this object has a different name.


Thank you,
Ryan

 

[Dr.Peterson]

I'm wondering what I would describe as a 'rectangular pyramid' with a equal slope on all sides is actually called? The fact it has an equal slope on all sides means that it has a line for it's top apex not a point.

The equal slope is not actually a necessity for the object I'm chasing a name for, its just the easiest way for me to describe a rectangular pyramid that culminates in a line for an apex.

All definitions I can find for 'pyramid' have a point for an apex, therefore I can only assume that this object has a different name.

Not all shapes have precise mathematical names; some only fit into more general categories, such as polyhedron.

In real life, this is called a hip roof; for some geometry about it, see here. That may be the best-know name for it; but it generally requires the same slope all around, or at least only two distinct slopes.

Geometrically, one name for it (not commonly used, to my knowledge) is oblique wedge. This appears to assume symmetry.

One place where this shape appears is in constructing a regular dodecahedron from a cube, by adding what are commonly called six "roof-shaped pieces", as shown here. I am not aware of any other name being used for these!

I am not aware of a name for the most general case you are asking about, where none of the slopes need be the same. I do know that if you needed formulas for its volume, you could treat it as a degenerate prismoid, with one dimension equal to zero. I have worked with that sort of shape before.