If a cyclic quadrilateral is inscribed in a circle
of a coaxal system such
that one pair
of connectors touches another circle
of the system at
, then each pair of opposite connectors will touch a circle
of the system (
at
on
,
at
on
,
at
on
,
at
on
,
and
at
on
),
and the six points of contact
,
,
,
,
, and
will be collinear.
The general theorem states that if ,
, ...,
are any number of points taken in order on a circle
of a given coaxal system so that
,
, ...,
touch respectively
fixed circles
,
, ...,
of the system, then
must touch a fixed circle
of the system. Further, if
,
, ...,
touch respectively any
of the circles
,
, ...,
, then
must touch the remaining circle.