Question

A regular 18-sided polygon is rotated with the center of rotation at its center. What is the smallest degree of rotation needed to map the polygon back on to itself?

Answer 1

360/18=20 therefore the smallest degree of rotation would be 20

Answer 2

It will be easier to explain how to solve this question in a square. If you rotate 4-sided square from the centre, you need to rotate it 90 degrees. The formula for this would be: 360 ° /the side count. In a square, it would be 360° /4= 90°.

In 18-sided polygon, the calculation would be: 360°/ 18 side= 20°