Answer:
The shape with a rotational symmetry would remain the same when rotated
The shape with the smallest angle of rotational symmetry of 180 degrees is shape D
How to determine the shape?
To do this, we simply examine each of the options
Shape A: Cross
The shape has 4 equal sides.
So, the smallest angle of rotational symmetry is:
Angle = 360/4
Angle = 90
The smallest angle of rotational symmetry is 90 degrees
Shape B: Star
The shape has 5 vertices.
So, the smallest angle of rotational symmetry is:
Angle = 360/5
Angle = 72
The smallest angle of rotational symmetry is 72 degrees
Shape C: Composite figure
This shape has a square and a triangle merged together at two ends
This means that the smallest angle of rotational symmetry is a complete rotation of 360 degrees
Shape D: Circle
The circle is divided into two equal segments.
The angle on the straight line of each segment is:
Angle = 360/2
Angle = 180
The smallest angle of rotational symmetry is 180 degrees
Hence, the shape with the smallest angle of rotational symmetry of 180 degrees is shape D