The diagram shows a circle with centre \(O\) and radius \(8\) cm. The points \(A\), \(B\), \(C\), and \(D\) lie on the circumference of the circle. Angle \(AOB=\theta\) radians and angle \(COD=1.4\) radians. The area of sector \(AOB\) is \(20\text{ cm}^2\).

(i) Find angle \(\theta\).

(ii) Find the length of the arc \(AB\).

(iii) Find the area of the shaded segment.