What's Special About Inscribed Angles?

We have already seen that a central angle shares the same measure as the arc it cuts off. How do inscribed angles fit in the mix?
1) DEFINITION: An [u]Inscribed Angle[/u] is an an angle with its vertex on the edge of the circle.[br][br]2) Two of the three circles below show inscribed angles. [b]Which one doesn't?[/b][br][br]3) What do you notice about the size of an inscribed angle when compared to a central angle cutting off the same arc? (Be specific - Drag the identified points to investigate your claim!)

Information: What's Special About Inscribed Angles?