The youtube presenter clearly only has a partial understanding of geometry.

The presenter selects center point arc tool and then carefully tracks over from the end of the arc - this implies tangency.
But Inventor did not automatically add the tangent constraint and then the presenter overrode by adding unnecessary dimension and trimmed without connecting the endpoint at other end (note that the sketch is still unconstrained).
Only two dimensions and a tangency are needed.
I would eliminate the 1.651 dimension as it is fantasy anyhow.
Only the radius and the 6.35 and tangent are needed. The 1.651 will be solved by the geometry conditions. It is what it is.
Logic must be a part of the design process.
The presenter started out creating the arc using a logical process but then got lost when the endpoint did not match a rounded off calculation distance. Use geometry.
Q2. What is 1.701-1.651=? State answer in terms of ratio of the thickness of a sheet of paper.
BTW - when you cite a source of information - you should reference the timestep so that it is easy to find.
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