Formulae: Can I Use a Volume Formula?

You should know the following formulae to work out the volumes of these 3D solid shapes:

 

Cube

 

You must know:

• the side length.

 

Remember that the length, the width and the height will all be equal to the side length, because this is a CUBE.

 

Volume of cube = side length × side length × side length

 

 

Cuboid

 

You must know:

• the length
• the width
• the height.

 

Volume of cuboid = length × width × height

 

 

Example 1

Can a volume formula be used to work out the volume of this cuboid, and if so, which one is best?

 

Answer

This is a cuboid.

We must know:

• the length
• the width
• the height.

 

The length is 15 cm, the width is 4 cm and the height is 8 cm.

 

Yes, we can use the volume formula:

Volume of cuboid  = length × width × height

 

 

Example 2

Can a volume formula be used to work out the volume of this cube, and if so, which one is best?

 

Answer

This is a cube.

We must know:

• the side length.

 

The side length is 7 cm, so the width and the height are also 7 cm.

 

Yes, we can use the volume formula:

Volume of cube  = side length × side length × side length

 

 

Example 3

Can a volume formula be used to work out the volume of this cuboid, and if so, which one is best?

 

Answer

This is a cuboid.

We must know:

• the length
• the width
• the height.

 

The length is 9 cm, the width is 4 cm but we do not know the height.

 

No, we cannot use a volume formula.

NB The length, the width and the height are all interchangeable with each other, depending on how you look at a cuboid.