The perimeter of the base of a cone is called the "directrix", and each of the line segments between the directrix and apex is a "generatrix" or "generating line" of the lateral surface. (For the connection between this sense … See more

Volume
The volume $${\displaystyle V}$$ of any conic solid is one third of the product of the area of the base See more

The definition of a cone may be extended to higher dimensions; see convex cone. In this case, one says that a convex set C in the real vector space $${\displaystyle \mathbb {R} ^{n}}$$ is a cone (with apex at the origin) if for every vector x in C and every nonnegative … See more

• Weisstein, Eric W. "Cone". MathWorld.
• Weisstein, Eric W. "Double Cone". MathWorld.
• Weisstein, Eric W. "Generalized Cone". MathWorld See more

In projective geometry, a cylinder is simply a cone whose apex is at infinity. Intuitively, if one keeps the base fixed and takes the limit as the apex … See more

• Bicone
• Cone (linear algebra)
• Cylinder (geometry)
• Democritus See more