Cone
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If a line moves in the space so that one end is kept fixed (point A) while the other end of the line is moved around the closed curve, the surface formed is called closed conic surface. The point A is called the apex. The area of the closed curve is called the base of the cone.
If the base of the cone is a circle, it is called a circular cone. If the base is a polygon, it is called a pyramid.
If the base of a cone is a polygon and the height from the apex is in the midpoint of the polygon, it is called a regular cone. A circular cone is called a right circular cone if the perpendicular height from the apex comes to the midpoint of the base.
Volume of a cone:
where A is the area of the base and h is the perpendicular height of the cone.