I’m only half through the sample chapter but this looks like a great way to simplify Trig for high-school students. Anything that produces simple algebraic formulae, is bound to be easier for students to learn.
Of course, the /. people are already bitching that this isn’t a “new foundation” of trig, simply a redefinition. It relies on the same theoretical foundation. However, who decided that the formulae we’re using now are in the best form. Sometimes Math needs to be as open to change as Physics 
hahhaah That was totally just flamebait. I’m going to get calculators thrown at me on the street 
Slashdot | Trigonometry Redefined without Sines And Cosines
“Dr. Norman Wildberger, of the South Wales University, has redefined trigonometry without the use of sines, cosines, or tangents. In his book about Rational Trigonometry (sample PDF chapter),
he explains that by replacing distance and angles with new concepts:
quadrance, and spread, one can express trigonometric problems with
simple algebra and fractional numbers. Is this the beginning of a new
era for math?”