(a) The diagram shows an isosceles triangle. Find the value of \(\theta\) in radians.

(b) The diagram shows a shape made of two arcs. Each arc is part of a circle with radius \(5\text{ cm}\). The height of the shape is \(8\text{ cm}\).

Use your answer to part (a) to find (i) the perimeter of the shape and (ii) the area of the shape.