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avatar+97 

Help me on this qeustion please.

 

  1. Solve for the length of the indicated side. Using knowledge that COS(150) = - (sqrt(3)/2) calculate the value of ‘x’ leaving your answer as an exact value.
 Feb 14, 2019
 #1
avatar+100516 
+1

We know two sides and an included angle....and we are looking for the opposite  side

 

The Law of Cosines is what we need....so

 

x^2 = 8^2 + 12^2 - 2(8)(12)cos 150     simplify

 

x^2 =  64 + 144 - (192) (-sqrt (3) / 2)   

 

x^2 =  64 + 144 + (192) (sqrt (3) / 2)     take the square root of both sides

 

x =  √ [ 64 + 144 + (192) (sqrt (3) / 2) ]   

 

x ≈   19.35

 

 

cool cool cool

 Feb 14, 2019
 #2
avatar+97 
+1

Oh so you replace the Cos 150 with sqrt(3)/2...

I thought you had to solve that lol.

I need to read the qeustion slower.angrysmiley

StarStrike  Feb 14, 2019
 #3
avatar+100516 
0

Be careful....cos 150   =    - sqrt (3)  / 2

 

cool cool cool

CPhill  Feb 14, 2019

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