Respuesta :

Explicación paso a paso:

[tex]area = \pi {r}^{2} [/tex]

[tex]as = \frac{3}{4} \pi {r}^{2} [/tex]

[tex]as = \frac{3\pi {(12cm)}^{2} }{4} = 339.292 {cm}^{2} [/tex]