Simply because square cases are easier to manufacture - and more stable. A square case will stand on end quite happily, whereas a circular case would roll.
Mathematically, the shape is known as a toroid. More prosaically, it is a circular disk with a smaller circular disk removed from its centre.
If r is the radius of the disc, then pi*r2 square units.
If the disk is circular, the area of one circular face is 112.72 X pi = 3.990 X 104 square kilometers, to the justified number of significant digits.
In art and symbolism, a crescent is generally the shape produced when a circular disk has a segment of another circle removed from its edge, so that what remains is a shape enclosed by two circular arcs of different diameters which intersect at two points.
A track is a circular ring on one side of the disk.
A disk.
Pall- cover Paten- disk shapePurificator- rectangular shape linenChalice- cupciborium- vessel for the hostscorporal- square shape linen
It is protected with a plastic cover and will not be scratched like DVDs and because it is square in shape it is easier to transport.
They Thought it was a flat disk
it is the hard disk
cd/record
RECORD is the right answer.. *_*