Question

Are all diagonals also lines of symmetry in a polygon?

Answer 1

No not all diagonal lines are lines of symmetry! Because if you take a piece of notebook paper and fold it in half the side do not match up! hope this helps :)

Answer 2

No, they are not. Here's an example.

The image attached is a hexagon. All of the lines drawn in are some of the diagonals. The diagonal with the arrow, however, is not a line of symmetry. Therefore, not all diagonals are lines of symmetry.