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oksteph · Oct 19, 2009

how do u solve this?

mitchy_boy · Oct 19, 2009

cosine rule

mitchy_boy · Oct 19, 2009

General covers that doesn't it?

lychnobity · Oct 19, 2009

oksteph said:
how do u solve this?

In any triangle, the angle opposite the smallest side, is the smallest angle.

Using that, the angle opposite to the 6, is the smallest. Then use the cosine rule:

$\cos C = \frac{a^{2} + b^{2} - c^{2}}{2ab}\\\\\cos C = \frac{7^{2} + 8^{2} - 6^{2}}{2(7)(8)}\\\\\cos C = \frac{11}{16}\\\\C = 47\degree$

.'. answer is B

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