1. Copyright 2013 Davitily

2. Find Missing Angles and Sides Using the Law of CosinesB
Step 1:
Apply the Law of Cosines to the triangle.
Step 2:
Select which formula to use.
Step 3:
Solve for the unknown.
Step 2:
Select which formula
to use. b a
a 2 = b 2 + c 2 −2bc⋅cos A b 2 = a 2 + c 2 −2ac⋅cos B c 2 = a 2 + b 2 −2ab⋅cos C C
Step 1:
Apply the Law of Cosines to the triangle.
a 2 = − ⋅cos o
Step 3:
Solve for the
unknown.
a 2 = −465.12⋅cos o
a 2 = −
a 2 = a=
=18.504=18.5

3. Find the Angles and Sides Using the Law of CosinesB
Step 1:
Apply the Law of Cosines to the Triangle.
Step 2:
Select which formula to use.
Step 3:
Solve for the unknown.
Step 2:
Select which
formula to use. b
18.5 a
a 2 = b 2 + c 2 −2bc⋅cos A b 2 = a 2 + c 2 −2ac⋅cos B c 2 = a 2 + b 2 −2ab⋅cos C C
Step 1:
Apply the Law of Cosines to the triangle.
= − ⋅cos B o
Step 3:
Solve for the unknown.
234.09= −562.4⋅cos B o
234.09=573.29−562.4⋅cos B o
B o =arccos = 52.9 o
−339.2=−562.4⋅cos B o
C o = 180 o − 52.9 o − 74.7 o = 52.4 o
0.603=cos B o

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