1, cylinder
A polyhedron has two parallel faces with the same size, and the intersection lines of the other two adjacent faces are parallel to each other, so this polyhedron is a cylinder; In addition, columns can also be divided into regular columns and inclined columns.
2. Vertebral body
Vertebra refers to a three-dimensional figure including a cone and a pyramid. , defined by a circular or other closed plane base and a surface formed by line segments connecting each point on the base boundary to a common vertex.
3. Rotating body
The curved surface formed by the rotation of a plane curve around a fixed straight line in its plane is called the surface of revolution; This fixed line is called the axis of the rotating body; A geometry surrounded by a closed surface of revolution is called a body of revolution.
4, round
In a plane, a closed curve formed by a moving point rotating around a certain point with a certain length is called a circle. A circle has countless points.
5. Polygons
In mathematics, a plane figure consisting of three or more line segments connected end to end is called a polygon. According to different standards, polygons can be divided into regular polygons and irregular polygons, convex polygons and concave polygons.
Baidu encyclopedia-geometry