Respuesta :

We can use the law of cosines as follows:

[tex]7^2 = 8^2+10^2-2\cdot 8 \cdot 10 \cdot \cos(\theta)[/tex]

We can rewrite this equation as

[tex]49 = 164-160 \cdot \cos(\theta) \iff 160 \cdot \cos(\theta) = 115 \iff \cos(\theta)=\dfrac{115}{160}\approx 0.72[/tex]

carlosego

For this case we have by definition of the Cosines Law that:

[tex]7 ^ 2 = 10 ^ 2 + 8 ^ 2-2 (10) (8) [/tex]* cosΘ

[tex]49 = 100 + 64-160[/tex]cosΘ

[tex]49 = 164-160[/tex]cosΘ

[tex]49-164 = -160[/tex]cosΘ

[tex]-115 = -160[/tex]cosΘ

[tex]115 = 160[/tex]cosΘ

cosΘ= [tex]\frac {115} {160} = 0.71875[/tex]

Rounding off we have, 0.72

ANswer:

Option C

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