First lets work out the area of the circle using the formula
area = π r²
We already know that the radius is 5cm
π x 5² = 78.53981cm²
Now we work out the area of the rectangle
6 x 8 = 48cm²
Finally we subtract the two areas to get left with the shaded area
78.5381 - 48 = 30.54cm² (2dp)