[OS X TeX] circle using metapost

[NMPOST7]

Dear All,

having gone through quite a few tutorials and explanations, I am finally back in
the mailing list.

All I need to do it metapost is draw a circle  at a particular coordinate (x,y)
with a diameter of n.

The code is clear to me. However, I need to specify the coordinates and the
diameter.

draw fullcircle scaled 50;

Thanks

BR
suren