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The law of cosines is a² + b² - 2abcosC = c². Find the value of 2abcosC.
A. 20
B. 40
C. 37
D. -40​

The law of cosines is a b 2abcosC c Find the value of 2abcosC A 20 B 40 C 37 D 40 class=

Respuesta :

Answer:

C

Step-by-step explanation:

a = 4

b = 5

c = 2

C = arccos((a² + b² - c²) / 2ab)

C = arccos((16 + 25 - 4) / 2(4)(5))

C = arccos(37 / 40)

C = 22.33°

2abcosC

2(4)(5)cos(22.33)

40(0.925)

37