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| Question 1101467:  Find the largest angle in a triangle with sides 6.0 cm, 7.0 cm, and 8.0 cm.
 Found 3 solutions by  Alan3354, stanbon, ikleyn:
 Answer by Alan3354(69443)
      (Show Source): 
You can put this solution on YOUR website! Find the largest angle in a triangle with sides 6.0 cm, 7.0 cm, and 8.0 cm. ------------
 It's opposite the longest side.
 Use the Cosine Law.
 
Answer by stanbon(75887)
      (Show Source): 
You can put this solution on YOUR website!  Find the largest angle in a triangle with sides 6.0 cm, 7.0 cm, and 8.0 cm. ------
 The angle opposite the largest side is the largest angle.
 ----
 a^2 = b^2 + c^2 - 2bc*Cos(A)
 ------
 Cos(A) = [b^2+c^2-a^2]/(2bc)
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 Cos(A) = [6^2+7^2-8^2]/(2*6*7) = -0.9167
 ----
 A = arccos(-0.9167) = 156.44 degrees
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 Cheers,
 Stan H.
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Answer by ikleyn(52879)
      (Show Source): 
You can put this solution on YOUR website! . Find the largest angle in a triangle with sides 6.0 cm, 7.0 cm, and 8.0 cm.
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The angle opposite the largest side is the largest angle.
a^2 = b^2 + c^2 - 2bc*Cos(A)
Cos(A) = [b^2+c^2-a^2]/(2bc)
Cos(A) = (6^2+7^2-8^2)/(2*6*7) =  .
A = arccos(1/4) =   75.56 degrees (approximately). 
 
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