GoGeometry Action 122!

Creation of this applet was inspired by a post from Antonio Gutierrez (GoGeometry). Feel free to move any of the LARGE POINTS at any time. Interact with this applet for a few minutes. After doing so, please answer the questions that follow.

1.

What is the measure of the green angle? Explain how you know this to be true.

2.

What is the measure of the pink angle? Explain how you know this to be true.

3.

How can we formally prove the measure of the inscribed angle (at the end) is what is is? Why does this value ALWAYS REMAIN INVARIANT?

Quick (Silent) Demo