let's say you have a triangle. ABC (corners)
you are given the mesurements of two sides.
Sides AB and BC.
you are also given the angle of B.
You have to find the other side.

b=CA
do you use b² = a²+c²-2ac COS B ?
using the law of cosinus? ( im canadian, no idea on the english conversion of terms)

anyways, had this in class, simple revision but i couldn't find it anywhere in my old notes from previous years, if you could remind me of how do find the CA side, that'd be great..(i think i might have it...)

Yes, what you said is correct.

AC^2 = AB^2 + BC^2 - 2*AB*BC*cos(<ABC)

ah perfect! Is this the right forum to be asking these types of questions? or are they not advanced enough. i beleive i lost my math notes, so i might need more help in the near future :-\

[quote author=Zerg link=board=36;threadid=3931;start=0#msg32485 date=1070143839]
ah perfect! Is this the right forum to be asking these types of questions? or are they not advanced enough. i beleive i lost my math notes, so i might need more help in the near future :-\
[/quote]
Yes, there's nothing in the forum rules that discriminates basic math against advanced math.