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.