The small circle has a radius of 3 cm, the large circle has a radius of 7cm ( 4+3),
The area of the small circle is PI x r^2 = PI x 3^2 = 9PI square cm.
The area of the large circle is: PI x 7^2 = 49PI
Both segments of the circle from A to C is 120 degrees, which is 1/3 the area of the complete circle.
1/3 the area of the large circle = 49PI / 3 = 16.333PI
1/3 the area of the small circle = 9PI / 3 = 3PI
The shaded area = 16.33PI - 3PI = 13.33PI