SOLUTION: Find the angle B in an oblique triangle in which a=31, b=15, and c=17

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Question 227081: Find the angle B in an oblique triangle in which a=31, b=15, and c=17
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!


Given:system%28a=31%2Cb=15%2Cc=17%2CBETA=unknown%29
Cosine law;
b%5E2=a%5E2%2Bc%5E2-2ac%2Acos%28BETA%29

Let us isolate BETA:
2ac%2Acos%28BETA%29=a%5E2%2Bc%5E2-b%5E2 ---> cross%282ac%29%2Acos%28BETA%29%2Fcross%282ac%29=%28a%5E2%2Bc%5E2-b%5E2%29%2F2ac

BETA=cos%5E%28-1%29%281025%2F1054%29
red%28BETA=13.47%5Eo%29}, Answer

Thank you,
Jojo