Answer: C) 0.84
Step-by-step explanation:
Since According to the law of cosines ,
[tex]b^2= a^2+b^2-2abcos\theta[/tex]
Where,
b is the opposite side of [tex]\theta[/tex]
And, a and b are the adjacent sides of [tex]\theta[/tex].
Here, c= 5.7 , a = 9.8 and b= 10.2
Therefore, [tex](5.7)^2 = (9.8)^2+(10.2)^2-2\times 9.8\times 10.2\times cos\theta[/tex]
⇒ [tex]32.49= 96.04+104.04 - 199.92\times cos\theta[/tex]
⇒ [tex]199.92\times cos\theta= 200.08-32.49[/tex]
⇒[tex]cos\theta=167.49/199.92=0.83828531412[/tex]≈0.84
Thus, Option C is correct.
