# Rotational symmetry and lines of symmetry of a regular polygon - Lesson+Exploration+Practice

You have learned about rotational symmetry in this activity.
Now let's use the rotational symmetry of a regular polygon to explore its lines of symmetry.
The

**are straight lines that divide a shape into two equal parts, where one part is an exact reflection of the other. Select the number of***lines of symmetry**of your polygon, and***sides***it. Every time that the rotated polygon overlaps the original one, press the***rotate****button on top right, to get a copy of the displayed line stamped in the app. Complete the full rotation of your polygon. You can delete all the lines you stamped by pressing the***Stamp***button displayed below the***Erase***one.***Stamp*Consider your polygon and the lines you have stamped. Are these lines of symmetry for your polygon? Can you relate the number of lines of symmetry of a regular polygon and the number of its sides?

## Food for thought...

Now consider a circle, and the definition of lines of symmetry. How many lines of symmetry does a circle have?