Having trouble with the law of cosines...c=3, a=4, angle B equals 145.
So b^2=16+9-2(4)3(cos145)
=25-(24 x 0.883863374)
=25 - 21.212721 = 3.787279
Anybody see the fault in my math because side b looks like approx. 7

Question

Having trouble with the law of cosines...c=3, a=4, angle B equals 145. 
So b^2=16+9-2(4)3(cos145)
=25-(24 x 0.883863374)
=25 - 21.212721 = 3.787279
Anybody see the fault in my math because side b looks like approx. 7

anonymous · Answer

Problem 1: You should be working in degrees, not radians.
Problem 2: You haven't square rooted the final answer.

anonymous · Answer

well yeah it be the square root of 3.787279

anonymous · Answer

is my cosine of 145 in radians?

anonymous · Answer

Yes. You should make sure your calculator is working in degrees.
cos(145) = -0.81915...

nilankshi · Answer

rite

anonymous · Answer

thanks thats been bugging the hell outta me

nilankshi · Answer

never mind

anonymous · Answer

the cosine of 145 is negative