Expert: Paul Klarreich - 2/26/2006

Question
how would i do this?
 Given the triangle with b=4, c=10, and A= 84 degrees, what is the length of a?  

Answer
Hi, Dipti,

You wrote:
Subject:  Calculus/Trig
Question:  how would i do this???
Given the triangle with b=4, c=10, and A= 84 degrees, what is the length of a?  

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This is a Law of Cosines case.  Any time you have S-A-S, meaning two sides and the angle between them, it's L-o-C.

a^2 = b^2 + c^2 - 2bc cos A

a^2 = 16 + 100 - 2(4)(10) cos 84
a^2 = 116  - 80 cos 84

Now you can just use your calculator.  Mine gives 10.375