Definition:Symmetry Group of Isosceles Triangle

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Group Example

Let $\triangle ABC$ be an isosceles triangle whose apex is $A$.

Symmetry-Group-of-Isosceles-Triangle.png

The symmetry mappings of $\triangle ABC$ are:

the identity mapping $e$
the reflection $d$ in the line through $A$ and the midpoint of $BC$.

This group is known as the symmetry group of the isosceles triangle.


Cayley Table

The Cayley table of the symmetry group of the isosceles triangle can be written:

$\begin{array}{c|cccccc}
 & e & d \\

\hline e & e & d \\ d & d & e \\ \end{array}$


Also see

  • Results about the symmetry group of the isosceles triangle can be found here.