A cylinder is a three-dimensional geometric shape with two parallel circular bases connected by a curved surface. The distance between the bases is called the height, while the radius is the distance from the center of the base to its edge. Common examples of cylinders include cans, tubes, and pipes. Cylinders can be found in various fields, including engineering and architecture. They are often used in the design of storage tanks, pistons, and rollers due to their strength and ability to hold pressure. The volume of a cylinder can be calculated using the formula V = \pi r^2 h , where r is the radius and h is the height.