What is symmetry?

Symmetry is when you can cut a shape into two parts and the two parts are equal. For example, if you cut a piece of paper in the shape of a heart in half from top to bottom, the two parts would be equal. But if you cut it in half from left to right, the two parts wouldn't be equal. Therefore, a heart has only one line of symmetry. A nine-pointed star has 9 lines of symmetry. A parallelogram has no lines of symmetry.
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