Math Aids
Math Aids: Geometry
Great resource to practice and strengthen math skills pertaining to Geometry. Math worksheets are printable, may be customized, and include answer keys.
Wolfram Research
Wolfram Math World: Squares
MathWorld provides multiple definitions and formulas for the mathematical term, square.
Math Slice
Math Slice: Geometry Slice Special Test
A succinct test for assessing geometry concepts. Assessment is scored online giving immediate feedback. An excellent assessment tool.