Introduction to Cylinders


Some curved surfaces may be defined as generated by straight lines which are thought of as moving and changing their direction continuously. Suppose that the line AB cuts a fixed curve BC not in the same plane with a straight line.

If AB is allowed to move so that it always remains parallel to its first position and always intersects the fixed curve BC, it will generate a curved surface called a cylindrical surface.



A cylinder is a solid figure generated by a straight line moving to its original position, while its end describes a closed figure in a plane. It is thus a limiting case of a prism whose ends would be circles, ellipses and parabolas, etc.

If the generated line is perpendicular to the base, then the cylinder is known as a right cylinder, otherwise oblique.