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.
Jim Loy
Jl's Math Page: The Golden Rectangle and the Golden Ratio
This is a personal site from Jim Loy that describes the golden rectangle and the golden ratio. Includes several diagrams and pictures as well as formulas. A good background in math is helpful.