Posted by **Louis** on Sunday, September 23, 2007 at 11:07am.

I'm in gr 11 doing Trigonometry

14.2 = b

---- ----

sin38 sin 67

a = 46

--- ----

sin20 sin130

(10.7)^2 = (9.5)^2 + (12.4)^2 - 2(9.5)(12.4) cos <B

I just need someone to explain this to me because I just don't get it... thank you for any help

- Math -
**bobpursley**, Sunday, September 23, 2007 at 11:17am
You are dealing with the law of sines and cosines. I am not certain what you don't get. Is it the algebra?

1) b=14.2*sin67 / sin38 put these in the calculator and compute.

2) Same issue:

a= 46*sin20/sin130

3) Law of cosines:

cosB= ((10.7)^2 - (9.5)^ - (12.4)^2 )/[(9.5)(12.4)]

Then to find angle B, take the inverse cosine of that result.

If you have questions, ask.

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