Radius Calculations?????

I had to scratch my head on this because I couldn't understand the question never mind get the answer.But I think I know where your coming from now.
The only calculi that I know that could be any use is 2 PI x R = C,where PI =
3.142,R=radius,C=circumference I don't know the radi so you work it out.
When you get the circumference if you want to divide it into 10 degree segments,divide 360 by 10=36,divide the length of the circumference by 36
this gives you the length of the segments on the out side circumference,mark these segments on one face side and one face edge.
Do the same thing on the inside, minus 2" for the thickness of the board.
you now have the size of the in side segments.When the difference for example is 1" mark a line 1/2"either side of the face side line,this is the top of the V you will cut out to form the radius.Join the lines on the top to the bottom of the line that is on the face edge.You now have all the marks you need good luck.
BTW we have just reinvented the wheel.