Introduction to Cone Cone is a geometric figure with two definitions. Analytic geometry definition: A spatial geometry consisting of a conical surface and a plane intersecting it (the intersection line is a circle) is called a cone. Definition of solid geometry: The geometry formed by taking the straight line where the right side of a right triangle is located as the rotation axis and the other two sides rotating 360 degrees is called a cone. The axis of rotation is called the axis of a cone. The surface formed by rotating a surface perpendicular to the axis is called the bottom surface of the cone. A surface that is rotated by an edge that is not perpendicular to the axis is called the side of a cone. No matter where you rotate, the side that is not perpendicular to the axis is called the generatrix of the cone. (An edge refers to two rotating edges of a right triangle)
The height of the cone: the shortest distance from the apex of the cone to the center of the bottom of the cone is called the height of the cone;
Cone generatrix: the radius of the sector formed by the expansion of the cone side and the distance from any point to the vertex on the circumference of the bottom surface.
Side area of the cone: The side of the cone spreads along the generatrix and is a fan. The arc length of this sector is equal to the circumference of the cone bottom, and the radius of the sector is equal to the length of the cone generatrix. The lateral area of a cone is the arc length and the circumference of the cone bottom × bus/2; It is a surface when it is not expanded.
A cone has a bottom surface, a side surface, a vertex, a height, and countless generatrixes. The development diagram of the bottom surface is a circle, and the development diagram of the side surface is a fan.