Irregular shapes don't ever have rotational symmetry.
none shapes have 1 rotational symmetry because in rotational symmetry one is none
Nothing has 1 order of rotational symmetry because in rotational symmetry 1 is none.
squares
circle
squarerhombusdiamondrectangle
A circle, square, and a triangle all have rotational symmetry.
None normally because rotational symmetry is only applicable to 2 dimensional shapes such as polygons.
These are also known as asymmetric shapes.
Three dimensional shapes, generally, don't have lines of symmetry, but a circle has an infinite number is symmetry lines. 3D shapes also don't have rotational symmetry either, but a circle has an infinite number of that as well.
A trapezium does not have rotational symmetry.
Square, circle, equilateral triange! Hope I helped! :)