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'Nine-pin Triangles' printed from http://nrich.maths.org/
How many different triangles can you make on a circular pegboard
that has nine pegs?
You may like to use the interactivity to try out your ideas. If you
prefer to work on paper, you might find this sheet of
This text is usually replaced by the Flash movie.
Many thanks to Geoff Faux who introduced us
to the merits of the nine-pin circular geoboard.
The boards, moulded in crystal clear ABS
that can be used on an OHP (185 cm in diameter), together with a
teacher's guide, are available from Geoff at Education