When a point 
moves along a line through the circumcenter of a given triangle 
, the pedal circle of 
with respect to 
passes through a fixed point (the Griffiths point) on the nine-point circle of 
.
Griffiths' Theorem
See also
Circumcenter, Griffiths Points, Nine-Point Circle, Pedal CircleExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Griffiths' Theorem." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/GriffithsTheorem.html