Consider the square below:
Four different axes (or lines of symmetry) are shown.
You can prove this by printing this page and cutting out the squares and folding
along the dotted lines.
JavaSketchPad pages are provided for you to explore symmetry
with quadrilaterals and pentagons. Move the red points until the original
figure and the reflection image are superimposed (i.e., when they figure and
image are on top of each other). When you have accomplished this the reflection
line is now the axis or line of symmetry for the figure.