Answers are :
a. Shape does not change
b. Shape does not change
c. Shape does not change
d. 270 degree rotation will not change the shape
e. Circle shape will not change its shape no mater it’s rotation
See my print screen showing how I got these answers
Assuming the points are all at equal angles, it can be rotated by 45, 90, 135, 180, 225, 270, 315 and 360 degree rotations without losing its rotational symmetry (looks the same). Rotational symmetry is found in circles, squares, rectangles, all regular polygons.
Take an object and spin it up to 180 degrees around its center. If the thing appears exactly like it did before rotation at any point, it has rotational symmetry.