A church spire is being renovated. The timber structure is shown below. It is the shape of an eight-sided (octagonal) pyramid. In plan, the edges of the octagon are 3.2 m long and the vertical height...

A church spire is being renovated. The timber structure is shown below. It is the shape of an eight-sided (octagonal) pyramid. In plan, the edges of the octagon are 3.2 m long and the vertical height of the spire is 8.4 m.

Calculate:

• The length of the hip rafter to be replaced

• The length of common rafter to be replaced

• The total area of the roof to be re-covered with copper sheet.