April 17th, 2013, 03:58 AM  #1 
Member Joined: Apr 2013 Posts: 30 Thanks: 0  Cosine and Sine laws
Some help here please. Don't get these four questions. 
April 17th, 2013, 04:54 AM  #2 
Member Joined: Jan 2012 Posts: 80 Thanks: 0  Re: Cosine and Sine laws
For the first one you need to use the cosine law. There is a simple explanation here http://www.mathsisfun.com/algebra/trigcosinelaw.html So we can write: 
April 17th, 2013, 05:04 AM  #3 
Member Joined: Jan 2012 Posts: 80 Thanks: 0  Re: Cosine and Sine laws
For the second one you need to rearrange the cosine law. Plugging in the values: " /> 
April 17th, 2013, 05:14 AM  #4 
Member Joined: Jan 2012 Posts: 80 Thanks: 0  Re: Cosine and Sine laws
The third one you need to use the sine law for: We know that all the internal angles of a triangle add up to 180 degrees so: We know the length AC and the angle opposite it and we know the angle opposite the side we wish to calculate. 
April 17th, 2013, 05:15 AM  #5 
Member Joined: Jan 2012 Posts: 80 Thanks: 0  Re: Cosine and Sine laws
The fourth one is very similar to the third one.

April 17th, 2013, 06:25 AM  #6 
Member Joined: Apr 2013 Posts: 30 Thanks: 0  Re: Cosine and Sine laws
Thank you SO MUCH !!! thank you, again ! Question resolved. ~ 

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cosine, laws, sine 
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