Composite Solid with Half-Cylinder and Cylindrical Hole

In this question, take \(\pi \) to be \(3.142\).

The diagram below shows a solid which is made by attaching a half-cylindrical block with diameter of \(8\) cm and a height of \(9\) cm to a cuboid with length \(8\) cm, width \(5\) cm and height of \(9\) cm. The shaded region shows the cross-sectional area of the solid.

1. Find the cross-sectional area of the solid. Give your answers to \(3\) significant figures.

A round cylindrical hole with a diameter of \(2\) cm is drilled through the middle of the cuboid to form an artefact as shown.

2. Find the volume of the artefact. Give your answer correct to \(3\) significant figures.

The artefact needs to be applied with a protective layer.

3. Given that the protective layer costs \(\$0.50\) per cm\(^{2}\), find the total cost of applying the layer.