
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?
This text is usually replaced by the Flash movie.
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 Education
Initiatives