Respuesta :

mhanifa

Answer:

  • B. 11.42

Step-by-step explanation:

Use the law of cosines:

  • [tex]c = \sqrt{a^2+b^2-2ab*cosC}[/tex]

Substitute the values:

  • [tex]c = \sqrt{9^2+12^2-2*9*12*cos64}=11.42[/tex]
  • a=9
  • b=12
  • C=64

Use law of cosines

  • c=√a²+b²-2abcosC
  • c=√9²+12²-2(9)(12)cos64
  • c=√81+144-216cos64
  • c=√225-216cos64
  • c=11.42 approx