Drawing and measuring a line through two circles and ending at an intersecting edge

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Here's what I'm trying to do with a routine

then detect the two circles that are 2 inches apart. detect the line on the curve on the lower edge and measure line from the top circle to the intersection of the curve. This curve will not always be a nice curve, but it will be a hard edge. Like this:

I was hoping to get some help pointing me to the right direction or maybe functions that I should use or investigate.

Cheers!