The diagram shows a right-angled triangle \(ABC\) with \(AB=8\text{ cm}\) and angle \(ABC=\frac{\pi}{2}\) radians. The points \(D\) and \(E\) lie on \(AC\) and \(BC\) respectively. \(BAD\) and \(ECD\) are sectors of circles with centres \(A\) and \(C\) respectively. Angle \(BAD=\frac{2\pi}{9}\) radians.

(i) Find the area of the shaded region.

(ii) Find the perimeter of the shaded region.