Circles, Triangles and Reflections:
the ballerina's theorem.
I have given an
RIBBM Masterclass
with this title at Bath.
The class was based on the classical theorem that
the circumcircle of a triangle consists of precisely those points
whose reflections in the three sides are colinear.
For the purposes of presentation, I christened this "the ballerina's theorem",
since it tells a ballerina where to stand if she wants to line up her
reflections in three practice mirrors.
Currently available are:
Alastair King
(
A.D.King@maths.bath.ac.uk)
Department of Mathematical Sciences
University of Bath
Last update: 21 Mar 2001