The parallelogram has rotational symmetry of order 2.

Four

We know that, a shape has reflectional symmetry, if one half of it, is the mirror image of the other half. Letters of the English alphabet having reflectional symmetry about a horizontal mirror are both horizontal and vertical mirrors are H, I, O and X.

Copying the diagram and then completing all the figures such that each shape is symmetric about the mirror line(s) or line of symmetry, we get the following figures:

The multiple lines of symmetry of each figure are shown below:
This figure has 4 lines of symmetry which are shown by dotted lines.

The multiple lines of symmetry of each figure are shown below:
This figure has 3 lines of symmetry which are shown by dotted lines.

On completing all of the figures about their lines of symmetry which are given as a dotted line, we get the following figures:

Yes,we are able to recall the name of the complete figure and name of the each figure is written under figures.

On completing all of the figures about their lines of symmetry which are given as a dotted line, we get the following figures:

Yes,we are able to recall the name of the complete figure and name of the each figure is written under figures.

With respect to the given line(s) of symmetry, the other hole(s) are marked in the figures given below:

On copying the figure with punched holes, the axis of symmetry corresponding to the punched holes are shown by dotted lines in the figures given below

Let mark a point A on each figure and also, indicate the angle through which is to be rotated as shown below:

Now, to find the rotational symmetry,we proceed as follows:
For figure (a), it requires two rotations, each through an angle of 180°, about the marked point (X) to come back to its original position. So, it has a rotational symmetry of order 2.
For figure (b), it requires two rotations, each through an angle of 180°, about the marked point (X) to come back to its original position. So, it has a rotational symmetry of order 2.
For figure (c), it requires three rotations, each through an angle of 120° about the marked point (X) to come back to its original position. So, it has a rotational symmetry of order 3.
For figure (d), it requires four rotations, each through an angle of 90°, about the marked point (X) to come back to its original position. So, it has a rotational symmetry of order 4.
For figure (e), it requires four rotations, each through an angle of 90° about the marked point (X) to come back to its original position. So, it has a rotational symmetry of order 4.
For figure (f), it requires five rotations, each through an angle of 72°, about the marked point (X) to come back its original position. So, it has rotational symmetry of order 5.
For figure (g), it requires six rotations, each through an angle of 60° about the marked point (X) to come back its original position. So, it has rotational symmetry of order 6.
For figure (h), it requires three rotations, each through an angle of 120°, about the marked point to come back to its original position. So, it has rotational symmetry of order 3.

The order of rotation is 4 and angle of rotation of given figure is \(\frac { 360° }{ 4 } =90°\)

We know that, a figure has line of symmetry if there is a line about which the figure may be folded, so that the two parts of the figure will coincide and a figure has a rotational symmetry if after a rotation, the figure looks exactly the same. Then, the complete table is shown below:

We can show line of symmetry for given figure as

In the above figure, rotational angle will be 90°. So, rotational symmetry will take place as

Given figure will complete full rotation in 4 steps. So, its order of rotation will be 4.