Rotational symmetry is a characteristic of any perfect circle. This means that the shape can be rotated less than 360 degrees and still appear exactly the same. A circle is infinitely symmetrical, as it keeps an identical shape regardless of how many degrees it is moved or rotated.
An equilateral triangle and a square are other examples of shapes with rotational symmetry. An equilateral triangle maintains its symmetry when rotated 120 or 240 degrees, while a square is identical when rotated 90, 180 and 270 degrees. However, of the letters "C," "R," "H" and "A," only "H" is rotationally symmetrical, as it may be rotated 180 degrees and look identical, while the others are visibly different with even the slightest rotation.