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# cosine law

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Find cos A.

May 14, 2022

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You can use cosine law to find c first.

$$c^2 = 8^2 + 11^2 - 2\cdot 8 \cdot 11 \cos 37^\circ\\ c \approx 6.666344593$$

Then, use cosine law again to find cos A.

$$8^2 = c^2 + 11^2 - 2\cdot c \cdot 11 \cos A$$

Substitute the value of c calculated above. Can you take it from here?

May 15, 2022