3 years ago

TriangleABC has three sides with these lengths: AB=9, BC=40, and CA=41, What is the value of cos C?

Mathematics

1 answer:

Otrada [13]3 years ago

3 0

Answer:

9² = 40² + 41² - 2(40)(41) cos(C)

81 = 1600 + 1681 - 3280 cos(C)

81 = 3281 - 3280 cos(C)

-3200 = -3280 cos(C)

cos(C) = 3200 / 3280

cos(C) = 40 / 41

Step-by-step explanation:

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