Posted by Bobby on Tuesday, June 29, 2010 at 3:59pm.
Is this a triangle?
Law of Cosines:
a^2=b^2+c^2-2bcCosA
solve for a.
Then, law of sines:
sin46/a=sinB/b
solve for sinB, then B
LAW OF COSINES: CosA=(b^2+c^2-a^2)/2bc
Cos46=(16+64-a^2)/2*4*8.
Cos46=(80-a^2)/64, 80-a^2=64Cos46,
a^2=80-64Cos46=35.54, a=5.96=6.0
LAW of SINES: SinB/b=SinA/a
SinB/4=Sin46/6,Multiply both sides by 4: SinB=4*Sin46/6=0.4791, B=28.66=28.7
and easy way to check this is to grab your protractor and sketch it to see if it works.
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