First, we'll find the area of the large section, including the smaller section that is white.
Area of a circle: pi x r^2
A = pi x 7^2
A = 49pi x 120/360
A = 49/3 pi cm^2
Now, we'll find the area of the small section.
A = pi x 3^2
A = 9 pi x 120/360
A = 3pi cm^2
All that's left to do now is subtract.
49/3 pi - 3 pi
40/3 pi cm^2
(or 13 1/3 = 13.33 cm^2)
Hope this helps!