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Help on solving this trigonometry question.

Help on solving this trigonometry question.-example-1
User DLRdave
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1 Answer

21 votes
21 votes

Answer:

BC = 14.317821

Explanation:

Carnot’s theorem

BC^2 = AB^2 + AC^2 - 2 * AB * AC * cos(BAC)

BC^2 = 10^2 + 5^2 - 2 * 10 * 5 * -4/5

BC^2 = 100 + 25 -20 * -4

BC^2 = 125 + 80

BC^2 = 205

BC = √205

BC = 14.317821 cm


We use negative value of cos because we know that BC is the the longest side: in the operation we have - * - = +

User Caribou
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