1. Nets Slideshow 45, Mathematics Mr Richard Sasaki Room 307

2. OBJECTIVES Recall names of some common 3d Shapes Recall names of some common 3d Shapes Understand how nets are formed Understand how nets are formed Be able to build nets for different shapes Be able to build nets for different shapes (Please bring some scissors and glue for next lesson!)

3. SOME SIMPLE 3-D SHAPES Sphere CylinderCone Square-based pyramid Hemisphere

4. PLATONIC SOLIDS / CONVEX REGULAR POLYHEDRONS Tetrahedron Cube Octahedron Dodecahedron Icosahedron

5. PRISMS Cuboid Triangular Prism Pentagonal Prism Hexagonal Prism Heptagonal Prism Dodecagonal Prism Octagonal Prism Decagonal Prism

6. NETS What is a net? A net is an unfolded 3D shape laid flat (in 3D). Nets are usually made for polyhedrons. A net also makes it easy for us to see how many faces a shape has. Stating how many edges or vertices might be harder though.

7. NET – CUBE There are many ways to unfold the cube (or any 3D shape) but the most common is… If this is rotated or flipped, it is still the same net. How many nets for the cube are there?

8. ANSWERS

9. MAKING NETS If we make a net, we need flaps to glue, like this… We don’t usually need to draw these though. What edge will the flap marked touch? x o x o x o Try the next worksheets!

10. ANSWERS - EASY a.Tetrahedron, Cuboid (Rectangular Prism), Cylinder b.Cylinder iv. Tetrahedron ii. Cuboid v. Tetrahedron iii. Cuboidvi. Cuboid

11. ANSWERS - MEDIUM 1. Triangular Prism, Pentagonal Prism, Octagonal Prism, Hexagonal Based Pyramid b. Pentagonal Prism ii. Hexagonal Based Pyramid iii. Octagonal Prism 2. Each circular face is connected to another face by a point (with 0 length and width).

12. ANSWERS - HARD 1.Octahedron c. 8 faces, 6 vertices d. 12 edges 2. Two faces will be on the same side of the “bunch”/ group. 3. V = 2F – 4 (Difficult question, well done if you got this!)