If you have a circle with a radius of 10 ft. how do you determine the area of a sector whose central angle measures 120?

The area of any circle is  (pi) (radius)²

The area of the whole circle is    (pi) (10-ft)²  =  100 pi ft²

120°  is  1/3  of  360° .

So the area of a  120°  sector is  1/3  the area of the whole circle = (100/3) pi ft².

Ithink the answer should be b.