I'm math nerd, and there's no trig required to figure this one out. You just need to know your quilt length and width and the distance between each of your seams on your binding. (I'm assuming that your binding is made up of uniform length strips.)
Here's an example with a 90" x 92" quilt and a binding made up of 42" strips.
Quilt size: 92 x 90
Distance between binding seams = 42
Start on 92" side.
Distance from corner: 40 (See note)
Seam 1 position: 40 + 42 = 82 (92 - 82 = 10 from next corner) (this seam is on the first side)
Seam 2 position: 42 - 10 = 32 (90 - 32 = 58 from next corner) (this seam is on the second side)
Seam 3 position: 32 + 42 = 74 (90 - 74 = 16 from next corner)
Seam 4 position: 42 - 16 = 26 (92 - 26 = 66 from next corner) (this seam is on the third side)
Seam 5 position: 26 + 42 = 68 (92 - 68 = 24 from next corner)
Seam 6 position: 42 - 22 = 20 (90 - 20 = 70 from next corner) (this seam is on the fourth side)
Seam 7 position: 18 + 42 = 60 (90 - 60 = 30 from next corner)
Seam 8 position: 42 - 30 = 12 (92 - 12 = 80 from next corner) (this seam is on the first side)
Seam 9 position: 12 + 42 = 44 (92 - 44 = 48) (this strip will over lap the start of the binding by 4")
Note: The 40" in this example is the distance from the *final* corner to be bound and the start of the binding strip. Meaning that you are binding away from that corner. Those 40" are the last section to have the binding sewn on.
I'm willing to do the calculations for you with your exact quilt. You just have to tell me:
1) the length and width of your quilt
2) which side you will start binding on
3) how far from the final corner to be bound the start of the binding will be placed (40" in the example)
4) how far apart the seams are in your binding