The concept of plane:

Plane is the most basic concept, which is only described but not defined. It is a mathematical concept abstracted from real life (such as common desktop, blackboard surface, calm water surface, etc.) ), but it is essentially different from these objects. It has infinite ductility (that is, the plane has no boundary), and there is no difference in size, width and thickness. These properties of a plane are related to the infinite ductility of a straight line.

Note: This aircraft has the following characteristics.

Unlimited extension, regardless of size, width or thickness.

Therefore, it is incorrect to say that the plane circumference is 24CM in the question, and the question is meaningless.