Adding dimensions between center points of 2 arcs in drawing

I am looking to add a distance between 2 points [10 inches] like Pic 1. My query is I can only do so after placing 2 "points" from "sketch" tab like Pic 2. Wonder how those dots (points) came up in Pic 1

Thanks.

P.S. I use Solidworks 2012 x64

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