I would use the standard dimensioning tool rather than the smart dimension tool. In the second attempt, it looks like you need to hover over the lines that create the intersection a little longer. Also, I noticed you were holding over the arc of the radius rather than the lines.
Like @kjoiner said Distance Between works.
But don't forget about the M I C E keyboard shortcuts when you do it.
Mid, Intersect, Center, End.
Start the Distance Between command.
Move your mouse over the two lines, one then the other.
Press "i" on the keyboard then click the second line.
Are you trying to dimension parallel to the chamfer? If so, you want to use either the "by two points" option or the "use dimension axis" option. These are in the pull down box in the dimension between tool.
Use the point to point dimesion but make that your (by 2 points) is selected.