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tankabanditka [31]
1 year ago
9

The law of Cosines Is......​

Mathematics
2 answers:
Tresset [83]1 year ago
7 0

Answer:

C

Step-by-step explanation:

a² + b² - 2abcosC = c² ( subtract a² + b² from both sides )

- 2abcosC = c² - a² - b² ( multiply through by - 1 )

2abcosC = a² + b² - c²

a, b, c are the sides opposite vertices A, B, C

here a = 4 , b = 3 , c = 2 , then

a² + b² - c²

= 4² + 3² - 2²

= 16 + 9 - 4

= 25 - 4

= 21

iogann1982 [59]1 year ago
5 0

Answer: \Large\boxed{C.~21}

Step-by-step explanation:

<u>The goal of the question</u>

Find the value of 2abcosC

<u>Given information</u>

a = 4

b = 3

c = 2

<u>Given formula (Law of Cosine)</u>

c^2=a^2+b^2-2abcosC

<u>Substitute values into the formula (Leave 2abcosC as it is)</u>

(2)^2=(4)^2+(3)^2-2abcosC

<u>Simplify the exponents</u>

4=16+9-2abcosC

<u>Simplify by addition</u>

4=25-2abcosC

<u>Add 2abcosC on both sides</u>

4+2abcosC=25-2abcosC+2abcosC

4+2abcosC=25

<u>Subtract 4 on both sides</u>

4 + 2abcosC-4=25-4

\Large\boxed{2abcosC=21}

Hope this helps!! :)

Please let me know if you have any questions

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