Email Math Question on "Use of barycentric coordinates and law of levers"

Hello AlwaysLovely!
I am a seconday 4 student this year
if u can remember, you tagged at my blog somewhere last year and mistook me for a secondary 4 student then, this thus led me to your blog.
anyway, i got a maths question to ask. i know that you wrote on your blog to ask you about O level maths but i was reading a book on geometry proofs and saw a question that was proven by the use of barycentric coordinates and law of levers. i am rather interested in this way of proving so i tried to yahoo-ing for tutorials on barycentric coordinates and was lost by some of the very few tutorials posted on the net.
So, i was wondering if you can enlighten me on some basics of barycentric coordinates or perhaps email me some links to tuturials on barycentric coordinates that might be easier for a secondary school student to understand.
i look forward to your reply and thanks!