3-D work: the extra dimersion

3-D work: the extra dimersion

1. Identifying solids

   • Prism
     • A prism has the same shape all the way through.
       • Its sides are parallel
         • So are its ends
   • Drawing 3D shapes on 2D paper
     • In mathematics 3-D shapes are drawn in special ways.
       • Hidden edges are shown by dashed lines.
   • Cube and cuboids
     • A prism takes its name from the shape of its end
       • Some prisms have special names
         • A cube and a cuboid are prisms
   • Pyramid
     • a pyramid is a solid whose side edges meet in a point
       • all its side faces are triangles
     • a pyramid takes its name from the shape of its base
     • the diagram shows a pyramid with a square base
   • Tetrahedron
     • A pyramid with a triangular base has a special name
       • it is called a tettrahedron
   • Polyhedron
     • a polyhedron is a solid whose faces are all plane (flat)

2. Using isometric paper

   • Drawing 3D shapes on isometric paper
     • a cude or cuboid can be drawn on isometirc paper with its edges shown their correct lenghts
       • the dashed lines are for the hidden edges are often missed out .

3. Nets of cubes and cuboids

   • Net
     • A net is a pattern of shapes on a piece of paper or card
       • the shapes are arranged so that the net can be folded to make a hollow solid
   • fact about nets
     • a cuboid also has six faces but they are not all the same size