I don't necessarily have a direct solution for your problem but would like to offer this up as it may help you figure out what's wrong:
If you're saying that the 862.861 dimension in the first pic is correct, it seems unlikely that the 638.372 dimension in the second pic is the missing part of the circle. Just eyeballing, I'd put the missing part in the 400 range.
Also, I don't know if there's more to the sketch that's not shown but relations #14,16, and 22 seem unnecessary. At least, I was able to fully define a similar sketch without making those entities coincident with something else. It took me 4 tangent relations, 2 radius dims, 1 coincident relation, 1 arc length dimension, and 1 linear dimension to define the sketch. The only coincident one was to make the center of the big arc coincident with the origin. That might be part of the problem.
Hope this helps...