What is the minimum angle of rotational symmetry for the quadrilateral?

The minimum angle of rotational symmetry for a quadrilateral is 90 degrees. This means that if you rotate the quadrilateral by 90 degrees around its center, it can align with its original position. However, a general quadrilateral does not have rotational symmetry unless it is a special type, such as a rectangle or a square. In those cases, the symmetry can be 90 degrees or less, with a square having 90 degrees and a rectangle having 180 degrees.