another way of thinking about it - a circle is 360 degrees.. a Square has 4 sides that add up to 360 degrees.. thus, 4 cuts of 90 degrees = 360 degrees.. In other words, divide 360 by the number of sides and that will be the angle you need to cut each side at... Now, if you want to find the length/width between angles to arrive at a desired diameter, then we're getting into more complex math.. (sines, cosines, tangents, PI, etc) But, if you don't care the diameter you get, (or length) then simply divide 360 by the number of sides, and you have your cutting angle. (So, 360 degrees divided by 6 means 60 degree angles.. if you needed 30 degree angles,for 12 sided pieces, since table saws don't cut at 30 degrees, so you have to "think backwards" and figure what angle is going to be 60 degrees (since table saw blade starts at 90 degrees, less the 30 you need, so you got to cut away 60 degrees of waste) Or, well.. if you go by the scale on your saw (0-45 degrees) then it's the other way around.. I just use a electronic angle gauge that attaches to saw blade by magnet...