PREVIOUSLY ASKED IN:
CTET 2026
Answer
E
Explanation
A figure has rotational symmetry if it looks exactly the same as the original after being rotated by an angle less than 360°. The letter O looks the same at almost any rotation. The letters H and N look exactly the same when rotated by 180°. However, the letter E does not look like itself until it is rotated a full 360°. Hence, E has an order of rotational symmetry of 1 (meaning no true rotational symmetry).
Key Points
- > Symmetry is primarily of two types: Line (Reflection) and Rotational.
- > The Order of Rotational Symmetry is the number of times a figure matches its original shape in a full 360° rotation.
- > Letter E has line symmetry (horizontal), but no rotational symmetry.
- > Letters H and O have both line and rotational symmetry.
- > Letters N, S, and Z have rotational symmetry (at 180°) but no line symmetry.
- > Every shape has at least an order 1 rotational symmetry (at 360°), which mathematically implies 'no rotational symmetry'.
Additional Information
Symmetry in English Alphabet
| Letter | Line Symmetry | Rotational Symmetry | Order |
|---|---|---|---|
| A, B, C, D, E | Yes | No | 1 |
| H, I, O, X | Yes | Yes | 2 (O is infinite) |
| N, S, Z | No | Yes | 2 |
| F, G, J, P, R | No | No | 1 |
Memory Tips
- The 180° Test: Turn your paper upside down. The letters that you can still read exactly the same (S, N, H, Z, O, X, I) have rotational symmetry.