Coming up in the triangle LS 10, this seam isn't quite a Y seam as there is no seam leading to the pivot point. I tend to tackle these a different way, working from the pivot out. First determine where the pivot point is.
Line up the two patches, using a pin to get the pivots together, and stitch the first side from the Pivot to the outside edge.
I have used contrasting thread so you can see my stitching, and I also do two or three backstitches when starting, to strengthen that part.
Determine where the pivot point is
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I mark the point on the fabric
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Line up with a pin
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