why is this the answer? PLEASE HELP

Answer:
[tex] A = \dfrac{512 \pi}{3}~ft^2 [/tex]
Step-by-step explanation:
area of sector, A:
[tex]A = \dfrac{n}{360^\circ}\pi r^2[/tex]
n = measure of the central angle of the sector in degrees
r = radius of circle
Here we have n = 240°, and r = 16 ft.
[tex]A = \dfrac{240^\circ}{360^\circ}\pi \times (16~ft)^2[/tex]
[tex] A = \dfrac{2}{3}\pi \times 256~ft^2 [/tex]
[tex] A = \dfrac{512 \pi}{3}~ft^2 [/tex]