<s>[INST] Two circles centered at A and B have radii of 3 cm and 4 cm, respectively. The circles touch external to one another along the line connecting their centers.
This means that the circles are tangential externally with a line running 
between the centers of the circles and where they touch at point c.
Therefore, the LHS of the diagram can be redrawn as per this conversation.

What is the length of the line connecting the centers of the two circles?[/INST]