3.65: Isosceles triangle and two-arc shape

The diagram shows an isosceles triangle with equal sides $5\,\mathrm{cm}$ and base $8\,\mathrm{cm}$. Find $\theta$ in radians.

The shape is made of two arcs, each part of a circle of radius $5\,\mathrm{cm}$, with height $8\,\mathrm{cm}$. Find the perimeter of the shape.

Find the area of the shape.