The radius is 10.4 cm. And the angle is 120 which is 1/3 of the circle.
Just use the area formula: 3.14 *r^2 to find the total area of 339.62 and then divide this by 3 to get 113.21. Then to subtract the triangle..find the area of the traingle which is 1/2 (10.4)^2 = 54.08. 113.21 - 54.08 = 59.13 which should be your answer