A square rotated about its center by 360º maps onto itself at 4 different angles of rotation. You can reflect a square onto itself across 4 different lines of reflection.
Solution:
When a square is rotated by an angle of 360°, at all four places that is when it is rotated by angle of 90° each time, at all four instances it is congruent to original square.
So, when a square is reflected along a line ,there are four lines through which square looks symmetrical.