Other
Dimension
This site contains a description of four dimensions through an example of spacetime. The site discusses how to determine the dimensions of a vector space and much more. Links are provided for further discoveries and understandings.
University of Toronto (Canada)
Question Corner: Higher Dimension Geometry
Use this site to discover how we represent higher dimensional objects in mathematics and how one might draw a four dimensional object on two dimensional paper and modeling fourth degree tetrahedron.