Creation of this applet was inspired by a [url=https://twitter.com/gogeometry/status/864976013712871425]tweet[/url] from [url=https://twitter.com/gogeometry]Antonio Gutierrez[/url]. [br][br][b][color=#1e84cc]What is the measure of the blue angle? [/color] [br]How can we formally prove that the 2 smaller segments are congruent? [/b]