what is the center of rotation for semi circle??

what is the order of rotation for semi circle??

Centre of the semicircle is the centre of rotation.

The order of rotation of a semi-circle is 1 as when we rotate it from 0° to 360° we get the exact image of semi-circle only once i.e., when it has been rotated at an angle of 360°. On other angles we will not get the exact image.