How many lines of symmetry does a square have?

The number of lines of symmetry in a regular polygon is equal to the number of sides of that polygon. A square has 4 sides. Thus use this information along with the concept explained previously to get the answer.

A regular square has 4 sides and 4 lines of symmetry. 

The number of lines of symmetry in a regular polygon is equal to the number of sides.

There are 4 lines of symmetry in a regular square.

 Two of them go from a vertex to the opposite vertex and two of them go from midpoint of side to the midpoint of the opposite side.

Consider a regular square ABCD as shown in figure the line of symmetry is also shown as 1, 2, 3, 4 which folds the square into two equal halves.

So, the regular square has 4 sides so the regular square has 4 lines of symmetry which folds the square into two equal halves.

Final answer:-

Hence option(D) is the correct option i.e. 4.