Air casan a thèid do chuideachadh a bhith a ' lorg an raon-cearcall a bhith aca air an trast-thomhas.
Cearcall – seo locus na points ann am plèana aig astar bho a gu thoirt seachad point called 's an cearcall does not exceed a chaidh a thoirt seachad àireamh ris an radius a' chearcaill ma tha radius a tha neoni an cearcall degenerates a point.
Tha trast-thomhas a tha dà thuras air a ' radius.