Here are examples of symmetry.

Notice the red line. It is a line of symmetry. It divides the square into two like halves.

This is a hexagon. A hexagon has 6 sides. Notice the line of symmetry.
The red line is a line of symmetry. It divides each shape into two  
like halves. Each half is the mirror image of the other. The colors,
shapes, and sizes are the same on each half. They are in the same
place on each half. This is called symmetry. 

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