Ratios and Proportions (time: 3:50)
http://www.youtube.com/watch?v=70xLo9jR81M
This is one of the best all around sites that I have
found. It is titled "The MacTutor History of Mathematics
Archive."
http://www-history.mcs.st-and.ac.uk/~history/
This is an award-winning site that links
to all sorts of mathematics information.
http://archives.math.utk.edu/
This site gives some practice with ratios.
http://www.purplemath.com/modules/ratio.htm
This site gives some practice with proportions. Scroll
down to the bottom and check out the next several pages
as well.
http://www.purplemath.com/modules/ratio2.htm
This site gives some examples of working with proportions.
http://www.mathleague.com/help/ratio/ratio.htm
