i know this is like 7th grade knowledge but i forgot . tried looking online but they gave me 100 different things i didnt need to know.
if you can give me just one example so i can remember that would be great
thanks
2007-10-04 17:45:05 · 4 answers · asked by Spys On Pedestrians 4 in Science & Mathematics ➔ Mathematics
Cosine rule
a² = b² + c² - 2bc cos A
2bc cos A = b² + c² - a²
cos A = [ b² + c² - a² ] / 2bc
Similarly:-
cos B = [ a² + c² - b² ] / 2ac
cos C = [ a² + b² - c² ] / 2ab
2007-10-04 21:50:19 · answer #1 · answered by Como 7 · 2⤊ 2⤋
you may use the law of cosines...here it is..
for a triangle with angles A, B, and C whose sides opposite these angles are a, b, and c, respectively, then...
a^2 = b^2 + c^2 - 2bccosA
b^2 = a^2 + c^2 - 2accosB
c^2 = a^2 + b^2 - 2abcosC
choose among these three...
btw, of course you will have to solve for either A, B, or C depending on what equation you use...
2007-10-04 17:54:17 · answer #2 · answered by tootoot 3 · 0⤊ 1⤋
http://en.wikipedia.org/wiki/Law_of_cosines
law of cosines, or a generalization of Pythagoras theorem
2007-10-04 17:50:35 · answer #3 · answered by Theta40 7 · 1⤊ 1⤋
remember sohcahtoa principle
2007-10-04 17:53:07 · answer #4 · answered by Anonymous · 0⤊ 1⤋