Question

what is the law of cosine

Answer 1

http://en.wikipedia.org/wiki/Law_of_cosines

Answer 2

like pythagoras but not for right triangles
\[a^2=b^2+c^2-2b c\ cos(A)\]

Answer 3

there's a diagram at the wikipedia site

Answer 4

i still can get this question thoough in tirangle ABC, a=8 b=9 and m of angle C = 135 what is the area of ABC

Answer 5

Area is base times height divided by 2, which can be found without the law of cosines, the height would be the sine of 135 times 8 if the base is 9

Answer 6

sin(135) = sin(45) = sqrt(2)/2
Area = 9*8*(sqrt(2)/2)/2

Answer 7

thank you that was an answer