We want to determine whether the figure has rotational symmetry. To do so, remember that in a rhombus, all four sides have equal length and the diagonals bisect each other. This means that the diagonals divide each other into two congruent parts.
Since the diagonals have different length, we have to rotate a rhombus by 180^(∘) to make it map onto itself.
This means that the given rhombus has rotational symmetry and rotations of 180 ^(∘) map it onto itself.
