See circle C below. You can adjust the length of the radius using the slider. [br][br]1. Move point A along the circle. Does the length of the radius ever change? What does moving A do?[br]2. Move points B or D along the circle. Does the length of the diameter ever change? What does moving B or D do?[br]3. Adjust the radius. What happens to the diameter when the radius is adjusted? How are they related?[br]   *If the radius is 2, what is the diameter? If the radius if 5, what is the diameter?[br]4.Could we come up with a formula relating the diameter and radius?[br][br][br]