Let
points
,
...,
be randomly distributed on a domain
, and let
be some event that depends on the positions of the
points. Let
be a domain slightly smaller than
but contained within it, and let
be the part of
not in
. Let
be the probability of event
,
be the measure of
, and
the measure of
, then Crofton's formula states that
(Solomon 1978, p. 99).