The circumcircle of the Johnson triangle 
has center at the orthocenter 
of the reference triangle and radius 
, where 
is the circumradius of the
reference triangle. It is therefore congruent
both to the circumcircle of 
and to the Johnson circles.
It has circle function
 |
where 
is the area of the reference triangle.
It passes through Kimberling center 
, which is the reflection of the circumcenter 
in the Jerabek center 
.
