Geometric anomoly?
March 10, 2005 5:11 PM Subscribe
Why is a rectangle not called a quadrangle?
First of all, it is, kind of: rectangle is a subset of quadrangle.
A "quadrangle" is a structure with 4 angles. Lots of things fit into this category, including rhombuses, trapezoids, etc.
A "rectangle" is structure with all right angles, that's what the "rect" part is for. I guess you could argue that it should more properly be called a "rectquadrangle" or something, but this is the word we've got. As you can see, there are lots of quadrangles that don't fit this definition.
Square is then a subset of rectangle, where all the sides are the same length.
posted by rkent at 5:20 PM on March 10, 2005
A "quadrangle" is a structure with 4 angles. Lots of things fit into this category, including rhombuses, trapezoids, etc.
A "rectangle" is structure with all right angles, that's what the "rect" part is for. I guess you could argue that it should more properly be called a "rectquadrangle" or something, but this is the word we've got. As you can see, there are lots of quadrangles that don't fit this definition.
Square is then a subset of rectangle, where all the sides are the same length.
posted by rkent at 5:20 PM on March 10, 2005
whoops, ignored the preview step... what those guys said.
posted by rkent at 5:20 PM on March 10, 2005
posted by rkent at 5:20 PM on March 10, 2005
"Quadrangle" is a general term for four-sided figures
Strictly speaking, Quadrangle is a general term for four-angled figures. "Quadrilateral" is the general term for four-sided figures. Not sure if or how you could have a figure that was one and not the other, but if you did, you'd be mighty glad the correct distinguishing term was available.
In terms of regullar usage, though, quadrilateral is the one I always heard referring to any (usually non-rectangular) four-sided figure, while every "quadrangle" (e.g. on college campuses) I've ever encountered has been a rectangle.
posted by soyjoy at 6:20 PM on March 10, 2005
Strictly speaking, Quadrangle is a general term for four-angled figures. "Quadrilateral" is the general term for four-sided figures. Not sure if or how you could have a figure that was one and not the other, but if you did, you'd be mighty glad the correct distinguishing term was available.
In terms of regullar usage, though, quadrilateral is the one I always heard referring to any (usually non-rectangular) four-sided figure, while every "quadrangle" (e.g. on college campuses) I've ever encountered has been a rectangle.
posted by soyjoy at 6:20 PM on March 10, 2005
A "rectangle" is structure with all right angles, that's what the "rect" part is for. I guess you could argue that it should more properly be called a "rectquadrangle" or something,
nope, no need - all right angles necessitates four sides.
posted by mdn at 6:56 PM on March 10, 2005
nope, no need - all right angles necessitates four sides.
posted by mdn at 6:56 PM on March 10, 2005
and tastefully color-coordinated!
posted by nebulawindphone at 9:39 PM on March 10, 2005
posted by nebulawindphone at 9:39 PM on March 10, 2005
Is that 90' or 270'?
posted by AlexReynolds at 11:23 PM on March 10, 2005
posted by AlexReynolds at 11:23 PM on March 10, 2005
Because rectilinear sounds cooler than quadralinear. Wait - no it doesn't... Because rectum... nevermind...
posted by raster at 6:50 AM on March 11, 2005
posted by raster at 6:50 AM on March 11, 2005
Obviously mdn meant convex euclidean planar shapes only, since there are also triangles with all right angles in elliptical geometry.
posted by techgnollogic at 2:30 AM on March 12, 2005
posted by techgnollogic at 2:30 AM on March 12, 2005
This thread is closed to new comments.
posted by kenko at 5:16 PM on March 10, 2005