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2 years ago

The law of cosines is a2+b2 - 2abcosC = c^2 find the value of 2abcosC .... A. 40 B. -40 C. 37 D. 20

1 answer:

8 0

A² + b² - 2abcosC = c²

Аngle C lies opposite to the side AB, so "c" in the formula it is AB in your triangle

4² + 5² - 2abcosC = 2²
16 + 25 - 2abcosC = 4
41 - 4 = 2abcosC
2abcosC = 37

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