How can you apply the segment addition postulate to a concept people use?

I have a geometry project i have to do and i have to write a paper on how you can apple the segment addition postulate to things that people could use. Segment addition postualte states that if you add the length of one segment to the length of another segment the number you get is both of them combined. Any ideas on how you can actually use this???How can you apply the segment addition postulate to a concept people use?
Well, when you're building a structure and you use lots of segments linked together to build it (like in a bridge), you can use the segment addition postulate to figure out the total length of all the segments linked together.