i am a little late on this blog but i rather get the 1/2 credit then the no credit so here we go. today im showing you the law of cosines. this is the last resort if law of sin does not work. the formula is opp leg^2=adj leg^2 + adj leg^2-2(adj)(adj) cos (angle b/w them). you can find angles or the other leg depending on what the directions are. usually it says solve and you will have to find everything so here is an example.
EX: solve the triangle
a=8 b=5 angle C=60 degrees
first you do the formula- c^2= 5^2 + 8^2 - 2(5)(8) cos 60
then square root everything and you get c=7
now find angle A- 8^2= 7^2 +5^2 -2(7)(5) cos A
move everything to the left and take in verse of cos A and u get A=81.787
now find angle B- 60+81.787= 141.787 then 180-141.787=38.213
now the triangle is solved
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