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In ΔABC, a = 260 inches, b = 480 inches and c=430 inches. Find the measure of ∠C to the nearest 10th of a degree.

1 Answer

5 votes
By the cosine rule

430^2 = 260^2 + 480^2 - 2(260)(480)cos(C)

C = arccos([260^2 + 480^2 - 430^2]/2(260)(480)

C = 63.1 degrees (nearest tenth of a degree)
User John Pasquet
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