Units of Area and Volume

Units of Area and Volume

GCSE(F),

An area consists of a length x width. The size of the length and the width are both measured using linear measurements, such as centimetres, metres, inches and feet. Because the calculation is a multiplication, the units are also multiplied together: multiplying 3cm by 5 cm gives 15 cm2: note the 2 after the cm.

When calculating areas, both measurements must be in the same units before attempting the calculation.

A Volume is a measurement of length x width x height: the units are also multiplied together: 3cm x 4cm x 5cm = 60cm3: note the 3 after the cm.

Volumes must also be calculated using the same measurement.

Examples

1. A tank containing fuel is 2m long, 1m wide and 1.5m high. What is the volume of the tank?

Answer: 3cm3

The calculation is 2 x 1 x 1.5 = 3.

Note that the answer is in cubic metres.

2. An advertising sign is being prepared. The sign is 1.2m wide by 45cm tall. It will be covered in a waterproof material. What area of waterproofing material will be required? Give the answer in square metres.

Answer: 0.54m2

Either convert 45cm to 0.45m, then calculate 1.2 x 0.45 to give 0.54.

Note that the answer is in square metres.