Suppose that we have two line segments, AB and CD. We know that they have the same length.
I know that $\overline{AB}=\overline{CD}$ means $AB$ is identical to CD (aka. They are the same lines), and also that $\overline{AB}\cong\overline{CD}$ means that $AB$ and $CD$ have the same size, but what does $AB=CD$ mean?
I actually saw this in a proof of the Transitive Property of Congruence. This is the proof:
Best Answer
In the horrible, no-good world of two-column proofs:
There are maybe some reasons to make the distinction between congruence of line segments and equality of lengths. But since nobody in high school geometry classes ever talks about those reasons, this is just an exercise in dealing with dumb definitions.