Answer: Option B. -> rotational symmetry
:
B
The letter 'S' whenrotated by an angle of ${180}^{\circ }$will look exactly the same as before.
Thus, it has rotational symmetry of order 2.
The letter S does not exhibit line symmetry.

Answer: Option B. -> False
:
B
Letters H and O have both line symmetry and rotational symmetry. Z has only rotational symmetry.

Answer: Option A. -> True
:
A
The statement is true.Diameter is the line of symmetry of a circle.

Answer: Option A. -> True
:
A
The statement is true.Diameter is the line of symmetry of a circle.

Answer: Option B. -> n
:
B
A regular polygon has as many lines of symmetry as the number of sides it has.
So, an 'n'-sided regular polygon has 'n' lines of symmetry.

Answer: Option B. -> n
:
B
A regular polygon has as many lines of symmetry as the number of sides it has.
So, an 'n'-sided regular polygon has 'n' lines of symmetry.

Answer: Option B. -> n−1
:
B
Angles of rotation of a regular polygon with ‘n’ sides = Y = n – 1
This is because the last rotation, i.e. ${360}^{\circ }$ is not counted as an angle of rotation. If it was counted as an angle of rotation, every object would have an angle of rotation.
So, angles of rotation for a square are ${90}^{\circ }$, ${180}^{\circ }$ and ${270}^{\circ }$. It’s only 3, not 4.

Answer: Option A. -> True
:
A
Rotational symmetry in biological sense is known as radial symmetry. They are things with same meaning but different names.
It is just like mirror/reflection symmetry.

:
A wind mill has order 3 rotational symmetry. Did you notice that after the third rotation, it looks exactly as it looked at the start? We got total of three instances where the wind mill looked exactly like as the start.
The key-point is the final position of any object, after 360° rotation will always look like the initial object. So, every object will have rotational symmetry of order 1.
Let us move on to the question now.

In 1, for 360° rotation, we have two instances where it looks like the starting position. That is after 180° and after 360°. So, the order is 2 which will be the value of ‘A’.
But fig. 2 has order 1 because it only repeats itself after 360° rotation. So, B = 1.
That means A + B = 2 + 1 = 3

Answer: Option B. -> Arjun is right and Shubh is wrong
:
B
If a figure can be folded along any line such that one half superimposes or aligns exactly with the other, it is known as symmetric figure.
For example: If you take a square and fold it across the line shown, part 1 exactly overlaps part 2. So, square is a symmetric figure.

On the other hand, in a parallelogram, the diagonal divides it into two congruent triangles (can be proven using SSS congruence condition), i.e.into two equal parts. But those parts don’t superimpose each other when folded across diagonal (as shown in the figure). So, parallelogram is not symmetric.


Hence, Arjun is right and Shubh is wrong.