A line where you put it in the middle of the shape and see if it's symmetrical or the same. You fold the shape and if one side matches to other, that is symmetrical. That is the line of symmetry.
A line of symmetry divides a figure into two parts such that each part is the mirror image of the other. In other words, if we flip one side of the figure over the line of symmetry, it should match up exactly with the other side.
