Rotational symmetry

Key Notes :

Rotational symmetry :

🎄The rotational symmetry of a shape explains that when an object is rotated on its own axis, the shape of the object looks the same.

🎇Many geometrical shapes appear to be symmetrical when they are rotated 180 degrees or with some angles, clockwise or anticlockwise. 

What is Rotational Symmetry?

🎄If a figure is rotated around a centre point and it still appears exactly as it did before the rotation, it is said to have rotational symmetry. A number of shapes like squares, circles, regular hexagon, etc. have rotational symmetry.

🎃There are many shapes you will see in geometry which are symmetrical rotationally, such as:

• Equilateral triangles
• Squares
• Rectangles
• Circles
• Regular Polygons

🎍Center of Rotation

🎟For a figure or object that has rotational symmetry, the fixed point around which the rotation occurs is called the centre of rotation. Example: the centre of rotation of a windmill in the centre of the windmill from which its blades originate.

✨Angle of Rotational Symmetry

🎪For a figure or object that has rotational symmetry, the angle of turning during rotation is called the angle of rotation. Example: when a square is rotated by 90 degrees, it appears the same after rotation. So, the angle of rotation for a square is 90 degrees.

🎉Order of Rotational Symmetry

🎊The number of positions in which a figure can be rotated and still appears exactly as it did before the rotation, is called the order of symmetry. For example, a star can be rotated 5 times along its tip and look at the same every time. Hence, its order of symmetry is 5.

Examples of Rotational Symmetry:

The recycle logo has an order of symmetry of 3.

The paper windmill has an order of symmetry of 4.

The triangle has an order of symmetry of 3.

The Swastik symbol has an order of symmetry of 4.

The roundabout road sign has an order of symmetry of 3.

Learn with an example

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