SYMMETRY - ROTATION -
Rotational Symmetry occurs when a shape or object looks the same after being rotated around a central point by a certain angle. If you can rotate the shape less than a full circle (360°) and it still matches its original appearance, the shape has rotational symmetry.
Key Features of Rotational Symmetry:-
Order of Rotation:-
The order of rotation refers to how many times a shape looks exactly the same within one full turn (360°).
360∘
Order of Rotation = -------------------
Angle of Rotation
Examples of Rotational Symmetry:-
1. Geometric Shapes:-
(a) Equilateral Triangle:- Rotational symmetry of order 3 (matches every 120° rotation).
(b) Square:- Rotational symmetry of order 4 (matches every 90° rotation).
(c) Circle:- Infinite order of rotation (looks the same at any angle).
2. Letters and Numbers:-
(a) Letters:- The letters H, N, O, S, Z exhibit rotational symmetry.
(b) Numbers:- The number 8 has rotational symmetry of order 2 (matches at 180° and 360°).
3. Natural Objects:-
(a) Flower petals:- Many flowers, such as daffodils, have rotational symmetry.
(b) Starfish:- A starfish with 5 arms has rotational symmetry of order 5 (72° rotations).
4. Objects and Patterns:-
(a) Propellers:- Rotational symmetry ensures the blades are evenly balanced.
(b) Fidget spinners:- These objects exhibit rotational symmetry, which gives them smooth spinning behavior.
Real-Life Applications of Rotational Symmetry:-