To find AB, we should use the Segment Addition Postulate. This postulate tells us that, if we have a point between two points, we can add the lengths of the two smaller segments to find the longer segment length. In our case, B is between A and C, so we can get the length AC by adding AB and BC.
AC = AB + BC
From the diagram, we know that the length AC is 10 and the length BC is 7. Now, we can use this to calculate AB.
