An exploration of how opposite angles of a cyclic quadrilateral relate to each other. Special cases of the angle at the centre theorem can also be deduced.

A dynamic exploration of the relationship between the angle at the centre of a circle and the angle at the circumference.

An exploration of the angle at the centre of a circle theorem that emphasises the centredness of the angle in relation to angles at the circumference of the circle.

By dragging the sliders you can select the coefficients of the quadratic equation and observe the roots that are generated.

The movement of the slider will generate a parabola for you to select the nature of the roots.


The VITALmaths and VITALmathsLIC site consists of a databank of short and funky video clips that specifically interrogate the conceptual aspects of a mathematical idea, process or concept. Some of the video clips contain strategic dialogues to encourage appropriate mathematical talk and conversation.
Visit the VITALmaths site


SANDBOXmaths is a collection of more experimental video clips done by students in their mathematics teacher-training classes and researchers wishing to use specific video clips in their teaching and research.
Visit the SANDBOXmaths site


The APPLETmaths site consists of a selection of GeoGebra applets that were developed by students and researchers for their research projects.

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