The diameter of the circle is 5.4 cm. The shaded area is 180 degrees, which is 1/2 of the circle.
Calculate the area of the full circle and divide by 2.
Area = PI x r^2
r = 5.4/2 = 2.7
Area = 3.14 x 2.7^2 = 22.90
Area of shaded part: 22.90 / 2 = 11.45 cm^2.
The answer is A.