Make five different quadrilaterals on a nine-point pegboard, without using the centre peg.
Work out the angles in each quadrilateral you make.
Perhaps checking that the four angles do add up to $360^\circ$!
Now, what other relationships you can see?
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For printable sets of circle templates for use with this activity, please see Printable Resources page
Many thanks to Geoff Faux who introduced us to the merits of the 9 pin circular geo-board.
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