need help with circles & arcs plz

What i'm hoping to do it put doors in a half circle. I know I need it split into 4 equal sections of 12.5 but can't for the life of me translate that into numbers for making the cuts when i'm building. Sorry if I seem a bit dense. I don't mind if it's difficult to do. Just need to know the secrets....... if any... to making these work.

Thanks in advance

Zarah
See attached picture for some idea of what i'm talking about

A simple technique for working with cuts is to use the arrows on the cut fields in the build tool. Clicking on the up and down arrows will adjust the cut by a small amount. Once you are in the general range, you can fine-tune by manually editing the numbers.

A cut of 0.125 will give you 1/8th of a circle, and multiply by an integer for that octant. These numbers are important because cuts on boxes start from the corners, so do get a squared off corner you need to use multiples of 0.125. For a cylinder it shouldn't be as much an issue. Combining cuts with rotations should give you tons of flexibility.

By the way, I prefer to work with cuts that are symmetric about the start end border, so I'll do a begin of 0.125 and end of 0.875. It can make doing texturing a bit easier. Speaking of texturing, probably the trickiest part is chosing your cuts so that you can get textures aligned properly, since you only have a few digits of precision to work with. If you can't get a texture aligned, change the cuts and rotation, then change the texture size/alignment for the new cut.

kk Thanks Olmy .... it'll help bunches...... and means a lot that you took the time to help.
*hug*