Copy of 5. Angles Subtended at Centre and Circumference

Angles at Centre and at Circumference
Move Points A and B to change the arc AB. Move Point D on the circumference of the circle.[br][br]How does the angle subtended (made) at the centre by the arc AB relate to the angle subtended at the circumference?
– willow26, David Smith

Information: Copy of 5. Angles Subtended at Centre and Circumference