Units of Measurement 4
Conversion of Units
It is useful to be aware of both metric and Imperial units and to be able to convert between them.
Imperial Units
| 1 foot | = | 12 | inches |
| 1 yard | = | 3 | feet |
| 1 mile | = | 1760 | yards |
| 1 pound (lb) | = | 16 | ounces |
| 1 stone | = | 14 | pounds |
| 1 gallon | = | 8 | pints |
Conversion Facts
| 1 kg is about 2.2 lbs. |
| 1 gallon is about 4.5 litres. |
| 1 litre is about 1.75 pints. |
| 5 miles is about 8 km. |
| 1 inch is about 2.5 cm. |
| 1 foot is about 30 cm. |
Worked Examples
1
John is measured. His height is 5 feet and 8 inches.
Find his height in:
(a)
inches,
Show meThere are 12 inches in one foot, so
| John's height | = 5 × 12 + 8 |
| = 60 + 8 | |
| = 68 inches |
(b)
centimetres,
Show me1 inch is about 2.5 cm, so
| John's height | = 68 × 2.5 |
| = 170 cm |
(c)
metres.
Show me1 metre = 100 cm, so
| John's height | = 1.7 m |
2
A family travels 65 miles on holiday. Convert this distance to km.
Show me
As 5 miles is approximately equal to 8 km, first divide by 5 and then multiply by 8.
| 65 ÷ 5 | = 13 |
| 13 × 8 | = 104 |
So 65 miles is approximately the same as 104 km.
3
John weighs 8 stone and 5 pounds. Find John's weight in:
(a)
pounds,
Show meThere are 14 pounds in 1 stone, so
| John's weight | = 8 × 14 + 5 |
| = 112 + 5 | |
| = 117 lbs |
(b)
kg.
Show meAs 1 pound is about 0.45 kg,
| John's weight | = 117 × 0.45 |
| = 53 kg (to the nearest kg) |
4
A line is 80 cm long. Convert this length to inches.
Show me
| 1 inch | = 2.5 cm |
| = 32, so the line is about 32 inches long. |
Exercises
