Triangle Sum Theorem (2022)

Instructions
Check the box to construct a line parallel to AC that goes through point B.[br][br]Slide the top slider to rotate the black angle 180 degrees.[br]Then, move the angle from point A to point B.[br][br]Slide the bottom slider to rotate the purple angle 180 degrees.[br]Then, move the angle from point C to point B.

Information: Triangle Sum Theorem (2022)