# How To Calculate The Volume and Area Of A Hollow Cylinder

What Is a hollow cylinder? A hollow cylinder is a cylinder formed by the space between an external cylinder and an internal cylinder. Now to understand this definition better, picture a cylinder inside another cylinder, and once you have done that, picture space in between the two-cylinder and that is what a hollow cylinder is.

### How To Calculate The Volume Of A Hollow Cylinder

To calculate the volume of the hollow cylinder, you would need to know the volume of the small/ internal cylinder, and the volume of the big/external cylinder. The volume of a hollow cylinder is the difference between the external and internal cylinder. The formula for calculating the volume is given by:

` V = π (R2 - r2) h where R is the radius of the external cylinder and r is the radius of the internal cylinder`

### Example

Find the volume of a hollow cylinder having inner radius = 7cm, outer radius = 14 cm and height = 7 cm. (Useπ = 22/7)

Using the formula

```V = π (R2 - r2) h
V = 22/7 *(142 - 72 )* 7 = 3,234cm3```

### How To Calculate The Area Of A Hollow Cylinder

The formula for calculating the area of a hollow cylinder is given by:

`2π ( r1 + r2)( r1 – r2 +h) where r1 is the external radius and r2 be the internal radius and h be the height of the given cylinder.`

### Lateral Surface Area Of A Hollow Cylinder

The formula for calculating the lateral surface area of a hollow cylinder is given by:

`2πRh + 2πrh where 2πRh is the external curved surface area and 2πrh is the internal curved surface area`

### Cross Sectional Area Of A Hollow Cylinder

The formula for calculating the cross-sectional area of a hollow cylinder is given by:

`2π(R + r)(h + R -r)`