Line of symmetry is a line which divides a figure into two equal mirror images. In an equilateral triangle, there are 3 such lines.

A square has 4 lines of symmetry.

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A mirror line helps to visualise a line of symmetry, a shape has a line of symmetry when half of it is the mirror image of the other half. But it is not applicable in the case of left-right changes in the orientation.
eg. R | Я
When the folded part sits perfectly on top (all edges matching), then the fold line is a Line of Symmetry.

Internal angle of regular polygon =  $\frac{(n-2)\times 180}{n}$
where, n is the number of sides.

Substituting, n = 6 in the above formula, we get internal angle as ${120}^{\circ }$ for a regular hexagon.

Every regular polygon has as many lines of symmetry as the number of its sides. So, they have multiple lines of symmetry.

Diagonal of a rectangle divides the rectangle into two triangles that are congruent, but folding along the line AB does not make the two triangles coincide with each other.

Hence AB is not a line of symmetry.

The order of rotational symmetry of a square about its centre is 4. The angle of rotation in a square is ${90}^{\circ }$.

A regular hexagon's order of  rotational symmetry is six.
Step 1: Order of rotational symmetry depends upon the number of equal sides that a regular polygon has.
Step 2: The given figure has 6 equal sides.
Step 3: So, it has rotational symmetry of order 6.

If a vertical line is drawn through O, perpendicular to the plane in which pentagon is drawn, then the vertical line is called axis of symmetry. Hence, the given statement is false.

A square has 4 lines of symmetry.

A rectangle has 2 lines of symmetry.

A regular pentagon has 5 lines of symmetry.

An isosceles triangle has only one line of symmetry.

Thus, the figures with more than one line of symmetry are: square, rectangle and regular pentagon.