Concept:A line of symmetry divides a shape into two identical mirror-image halves.
Explanation:A square has
4 equal sides and
4 right angles.
It can be folded along
4 different lines so both halves match exactly.
The vertical line through the centre is one line of symmetry.
The horizontal line through the centre is another line of symmetry.
Each diagonal of the square is also a line of symmetry.
So, the total number of lines of symmetry is
4.
In fact, for any regular polygon, the number of lines of symmetry is equal to the number of its sides.
Since a square is a regular polygon with
4 sides, it has
4 lines of symmetry.
Answer:D.
4