Final answer:
Parallelograms are formed by rotating a line segment 180 degrees around its midpoint, resulting in opposite sides that are parallel and equal in length.
Step-by-step explanation:
Parallelograms are created by rotating 180 degrees around the midpoint of a(n) line segment. When you rotate a shape by 180 degrees about a central point, each point on the shape follows a circular path around this central point. In the case of creating a parallelogram, we consider a line segment and its midpoint. Rotating the line segment 180 degrees around its midpoint will result in the formation of a parallelogram. This is because the original and rotated line segments are parallel and of equal length, and their midpoints coincide, thereby forming opposite sides of the parallelogram. It is noteworthy to mention that all points on the line segment maintain a consistent rotation angle and that the rotation angle (in this case, 180 degrees) is the amount of rotation analogous to linear distance.