Stage: 3 Challenge Level: 
The theme of this months problems is triangles - I think this is a good place to start but, does a suitable triangular box have a smaller surface area than a rectangular one? If not why not?
Circles. Pythagoras' theorem. Surface and surface area. Prisms. Short problems. Mathematical modelling. Creating expressions/formulae. Generalising. smartphone. Area.
Published November 2002,December 2002.
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