Use Segments and Congruence
Beginning by defining congruence, postulates, and axioms, I discuss the difference between congruent segments and equal lengths (distances). I talk about how the ruler postulate helps us measure lengths, and the segment addition postulate reminds us that the parts add up to the whole when points are collinear. I put the segment addition postulate in real life context when I talk about a road trip taking us to Wall, SD.