ACT02A Relationship Between Angles and Centre and Circumference
Point O is the centre of the circle. You can freely move: 1. Point C to control the size and position of the angle at circumference. 2. Points A and B to control the size and position of the angle at centre. Exploration: By moving point C, explore under what situation will the angle at circumference has a special relationship with the angle at centre. Draw the two different figures obtained during the exploration. Question 1. Suggest a relationship between angle at centre and angle at circumference sustained by the same arc. 2. In what way the arc length of angles sustained by the same arc affects the above relationship?