Chapter 11.5, Problem 4GP

To determine

To determine if the blades of the windmill have rotational symmetry and if they do then find the angle of rotation.

Answer to Problem 4GP

Yes

Angle of rotation: ${90}^0$

Explanation of Solution

Given:

A windmill

  

If the blades of a windmill are rotated by an angle of ${90}^0$ then the windmill will look exactly the same.

This shows that blades of the windmill have rotational symmetry.

And since they look exactly same after a rotation of ${90}^0$ so, the angle of rotation will be ${90}^0$ .

Conclusion:

Hence, blades of a windmill have rotational symmetry with an angle of rotation of ${90}^0$ .