Subject Enrichment 2
Shivranj Rasheel
a figure has rotational symmetry if it can be mapped onto itself by a rotation less than 360°. The minimum number of degrees it must be turned before first mapping itself is considered the Angle of symmetry.The order of the rotational symmetry is the number of positions ( all way around the figure ) at which point maps onto itself (order does include a a complete turn ) sometimes we are asked to provide all angles at which a figure maps onto itself in which case we do not include 360°.
What is Rotational Symmetry?
Name 2 objects with rotational symmetry
2 Objects with Rotational Symmetry
first aid sign
First Aid sign
ORDER OF SYMMETRY AND THE DEGREE OF Symmetry IN THESE objects
Order and degree of rotational symmetry
Starfish
Starfish : -
ORDER OF ROTATIONAL SYMMETRY - 5
Degree of Rotational symmetry - 72
First Aid sign :-
order of rotational symmetry - 4
degree of rotational symmetry - 73 degrees
First aid sign
What will be the order of rotational symmetry for a starfish with 5 arms. Find it's degree of rotation too.
rotational symmetry for a starfish
Its order of rotational symmetry would be 5 as it looks the same in 5 turns.
Degree of symmetry
The degree of rotational symmetry would be 73 degrees because 360 / 5 = 73 degrees
Order of symmetry
IS IT CORRECT TO SAY THAT THERE IS NO OBJECT WITH ORDER OF ROTATIONAL SYMMETRY?
Do all objects have rotational symmetry?
No,it is not correct to say that there is no object with 0 as rotational symmetry, as objects such as kites and trapezium do have rotational symmetry as 0
Answer
3
