Unformatted text preview: 2 + c 2 – a 2 Cos A = b 2 + c 2 – a 2 / (2bc) = 9 + 7 – 4 / (2 * 3sqrt(7)) = 12/(6sqrt(7)) = 2sqrt(7)/7 A = cos1 2sqrt(7)/7 = 40.9 o For angle B: b 2 = a 2 + c 2 – 2ac cosB Cos B = a 2 + c 2 – b 2 / (2ac) = 4 + 7 – 9 / (4sqrt(7)) = 1/2sqrt(7) = sqrt(7)/14 C = cos1 sqrt(7)/14 = 79.1 o Notice that A + B + C = 40.9 + 79.1 + 60 = 180, as required....
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 Fall '07
 BRUNSDEN,VICTORW
 Math, Trigonometry, Pythagorean Theorem, Dot Product, Law Of Cosines, Law of sines, triangle

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