## Definition of cylinder

A cylinder is a three-dimensional (3 d) solid shape that consists of two circles and a curved rectangle. Its two ends are circles of equal radius and curved lateral curves.

As you can see in the figure above, the two ends of this shape are circles of equal radius and the lateral face curve of this shape. Hence, this shape will be called cylinder.

## Properties of cylinder

A cylinder is a solid geometric shape, if we divide it, it will have two circles and a curved face. Those two circles will be called the bases of this cylinder. These two circles are congruent and parallel to each other.

The height of the cylinder is the vertical distance between these two bases. It is very important to find the height of a cylinder when it comes out.

The radius r of the cylinder is the radius of both circles. If the diameter of the cylinder is given to us, the radius can be deduced by dividing it.

The line that connects the centers of both the bases of a cylinder is called the axis of that circle.

**Volume of cylinder =** πr2h

**Curved surface area of cylinder =** 2 πrh

**Total (full) surface area of the cylinder =** 2 πr (r + h)

**Volume of hollow cylinder =** πr (R + r) (R-r)

**Where R** = outer radius of cylinder, r = inner radius of cylinder