How does the slop of AB
compare with the slope of the parallel line as you move points A, B, and C? What conclusion can you draw about the relationship between the slopes of parallel lines?
As points A and B move, the slopes of the two lines change but remain equal to each other. As point C moves, the slopes do not change but remain equal to each other since the line through C is drawn parallel to AB↔. I can conclude that the slopes of any two parallel lines are equal.
