Use this applet to investigate the relationship between the angle subtended at the centre of the circle and the angle subtended at the circumference.
Move point B around the circle to change the sizes of the angles.
Try to answer the questions given below

1. Move point B around the circle, first towards point A and then towards point C. Observe the relationship between the two angles marked. Copy and Complete the sentence below:
" The angle subtended at the centre is __________ the angle subtended at the circumference."
2. What happens when point B is between points A and C? (Hint: You may want to switch off angles p and q and switch on angles r and s)
3. The "picture" for this theorem looks quite different for some different positions of B (e.g. an arrow head, a quadrilateral.....etc). Draw some pictures for your notes to illustrate how this theorem looks for different positions of B.