2
edits
Changes
Jump to navigation
Jump to search
Line 1:
Line 1: + + + + + + + + + + + +
no edit summary
[[Image:Ghdyt.png|right|thumb|300px]]
[[Image:Ghdyt.png|right|thumb|300px]]
A '''Torus''' is the mathematical term for a “doughnut” shape created by rotating a circle around an axis.
If the “inner radius” (the size of the doughnut hole) is R, and the radius of the circular cross-section is r, then, the surface area of the torus is
:S = 4 π<sup>2</sup> (R+r)r
and the volume is
:V = 2 π<sup>2</sup>(R+r)r<sup>2</sup>
== Topology ==
A '''Torus''' can be defined as the [[cartesian product]] of 2 [[circle]]s. It can be constructed from a [[rectangle]] by identifying its opposite edges.
A '''Torus''' can be defined as the [[cartesian product]] of 2 [[circle]]s. It can be constructed from a [[rectangle]] by identifying its opposite edges.
This means that the torus surface is connected in the same way as the points on a rectangle, where you can “wrap-around” from one side of the rectangle to the other. This was a common topology used in the playing field of older video games.
[[Category:Geometry]]
[[Category:Geometry]]