are you guys sure about that cuboid thing? sounds like a factoid to me.
The perfect cite: http://mathworld.wolfram.com/RectangularParallelepiped.html
I think the suggestion is a useful one; they are related solids, in fact a cube could be described as a regular cuboid.
Cuboid is perfectly acceptable, despite my never having heard it before. However, we do have toroids and sphereoids, which are the class of objects shaped roughly like toruses and spheres, respectively.
I was going to say “hexahedron,” but I’m pretty sure that refers to anything with the same topography as a cube, including shapes with weird angles.
“Rectangular prism” is what I remember learning in grade school.
One problem with prism is that prisms don’t have toi be “right”, that is, extruded and a 90 degree angle. Take a rectangle. Then extrude it at a 45 degree angle. To visualize this, here is the plane of the rectangle edge on:
----/----
This is still a prism. So to describe a box / block shape “right rectangular prism” is more accurate. (tho “right” can probably be implied in non matematical contexts)
Brian
True, but perhaps regular hexahedron is another possibility for the solid’s name — making four now total.
Or how about “limiting super ellipsoid”? I’m sure that term would catch on, if we all start using it.
Surely this could only describe a cube, not any kind of rectangular prism/cuboid?
Ah, you’re right. Scratch that idea.
Is there anything wrong with “rectangular solid”?
“Rectangular parallelepiped,” though correct, is a hellacious mouthful to say, especially compared with nice simple words like “cube” or “sphere.” But as far as I know, there isn’t a single, simple word for it.
In a context in which I had to refer to one repeatedly, like teaching a math class, I’d probably call it a “rectangular solid” or “rectangular box” the first couple of times and then refer to it as just a “box” thereafter.
I 've never heard anything but “rectangular solid” for a technical term, and I don’t see why “box” is wrong or inadequate colloquially.
This might be a Britishism, but whatever happened to the word ‘Oblong’ as a substitute for rectangle?
Noel Fielding did a sketch on this, about how Oblong is a word that only five-year-olds and under can get away with saying.
Five year old “That’s an oblong”
Responsible adult “Er…no…I think you’ll find that’s a rectangle”
Is calling that a 3D-Simplex inaccurate?
I guess that would be like calling a triangle a 2D-Simplex, but 3D-Simplex was the first thing that popped into my mind.
Or is a 3D Simplex more general than that?
I’m going to start asking people in the office to start thinking outside the rectangular solid.
Wikipedia 's take on this:
The use of “maths” in this text suggests it was written by a Brit.
IMO time - ‘oblong’ sounds fairly old-fashioned to me
I believe that “box”, in mathematical usage, actually refers to a set in R[sup]n[/sup] describable by [a[sub]1[/sub],b[sub]1[/sub]] × [a[sub]2[/sub],b[sub]2[/sub]] × … × [a[sub]n[/sub],b[sub]n[/sub]]. So it would be quite proper to describe the figure in question as a “3-d box”, or in contexts where three dimensions may be assumed, merely “a box”. When you have a term which is both correct mathematically, instantly recognizable, and short, why not use it?
So, for those of you keeping score at home, we now have the following candidates:
rectangular box
rectangular parallelepiped
rectangular prism
rectangular solid
limiting super ellipsoid
3d simplex
cuboid
hexahedron
quader
The first four cancel each other out. Sorry, that’s just the breaks.
The definition I find for 3D Simplex is “A Euclidean geometric spatial element having the minimum number of boundary points”. In 3-D space, this would actually be a tetrahedron.
Limiting Super Ellipsoid sounds quite impressive, but I don’t really know what it is, no I’m discounting it.
Cuboid is technically correct, but as previously stated sounds too much like “cube”, so it’s out as well.
Hexahedron is good, but would apply to any three dimensional shape with six faces, so it is not specific enough.
So I’m sticking with Quader, which, if the Google transation is to be believed, is German for “right parallelepiped”. Since English is filled with “borrowed” words already, I see no problem in adding one more to the list.
Meh. Quader sounds like the name of a politician. Vote Cuboid!
A super ellipsoid is a three-dimensional shape that satisfies the equation:
(x/a)[sup]n[/sup] + (y/b)[sup]n[/sup] + (z/c)[sup]n[/sup] = 1
As the exponent n gets larger and larger, the shape more and more resembles a box with dimensions 2a by 2b by 2c — though it never actually becomes such a box.
Anyway, I wasn’t being serious in proposing “limiting super ellipsoid” as a replacement for “cuboid”, “rectangular prism”, or whatever. It’s just an amusing, arcane way of looking at a plain and simple shape.