Interior and Exterior Angles of a Heptagon.

Topic:
Angles
Interact with the applet below for a few minutes.   Then, answer the questions that follow.   Be sure to change the locations of the heptagon's BIG BLACK VERTICES each time before you drag the slider!!! Note: Each point on a side of this heptagon is a midpoint.
Questions: 1) What happened when you dragged the black vertices? 2) When you dragged the slider to the other end, what happened? 3) From your observations, what is the sum of the measures of the interior angles of     any heptagon?   4) Select Exterior Angles. What happened when you dragged the vertices? 5) When you dragged the slider to the other end, what happened? 6) From your observations, what is the sum of the measures of the exterior angles of     any heptagon?