What is the notation for the distance from A to C?

Answer 1

There are few different notations. Some people use the letterd for distance. So the distance from A to C would be d(A,C). The notation using d is nice because it does not specify and specific dimension. Furthermore, there are different ways of measuring distances. These are called metrics.

The usual metric is the distance formula often taught in Algebra classes. So another way to denote the distance is |A-C| where

the vertical bars mean absolute value. Of course the distance from A to C is the same as the distance from C to A so we could also write |C-A|. This notation measures what is known as the Euclidean distance.

Just as an aside, here is an example of another metric known as the Taxi Cab metric. Minkowski was the first to consider this I believe. I will place a link to a good Wikipedia article about it for those who are interested. Metrics are often studied in a branch of math known as Topology There is also a link to an article on metrics in general. It is interesting to see all the ways to measure "distance."