Respuesta :

DeanR

[tex]d^2=e^2+f^2-2ef \cos D[/tex]

[tex]d^2-e^2-f^2=-2ef \cos D[/tex]

[tex]\cos D = \dfrac{e^2+f^2-d^2}{2ef}[/tex]

[tex]\cos D = \dfrac{18^2+22^2-10^2}{2(18)(22)} = 59/66[/tex]

[tex] D= \arccos \dfrac{59}{66} \approx 26.63^\circ[/tex]