The circular field is basically the square of π r.

When making an apron, the upper, lower and lower areas are all high. The estimated capacity of different pot types is less than that of steel cylinders. When you make it, the actual size should be one size smaller. If the belly is round, the stone will be bigger than the cylinder. Therefore, for example, for a 220cc cylinder, the estimated capacity can be estimated as 2 10.

That's about it. Think for yourself.