### Reflections using coordinates

A reflection is a transformation that 'flips' a figure about a line. This line is called the **axis of reflection**.

In the figure above, \(\triangle ABC\) is reflected in the \(x\)-axis to the image \(\triangle A^\prime B^\prime C^\prime\). The axis of reflection is the \(x\)-axis.

In the same figure, \(\triangle ABC\) is reflected in the y axis to the image \(\triangle A^{\prime\prime} B^{\prime\prime} C^{\prime\prime}\). The axis of reflection is the \(y\)-axis.