Units of Measure
5.1 Units of Measure – Cheat Sheet
1. Metric Units – Length
| Unit | Relation to Metre | Conversion |
|---|---|---|
| 1 mm | 1/1000 m | 1000 mm = 1 m |
| 1 cm | 1/100 m | 100 cm = 1 m |
| 1 m | Base unit | – |
| 1 km | 1000 m | 1 m = 0.001 km |
2. Metric Units – Area
(Square units – conversion factors squared)
| Unit | Relation to m² | Conversion |
|---|---|---|
| 1 mm² | (1/1000 m)² = 1/1,000,000 m² | 1 m² = 1,000,000 mm² |
| 1 cm² | (1/100 m)² = 1/10,000 m² | 1 m² = 10,000 cm² |
| 1 m² | Base unit | – |
| 1 km² | (1000 m)² = 1,000,000 m² | 1 m² = 0.000001 km² |
3. Metric Units – Volume
(Cubic units – conversion factors cubed)
| Unit | Relation to m³ | Conversion |
|---|---|---|
| 1 mm³ | (1/1000 m)³ = 1/1,000,000,000 m³ | 1 m³ = 1,000,000,000 mm³ |
| 1 cm³ | (1/100 m)³ = 1/1,000,000 m³ | 1 m³ = 1,000,000 cm³ |
| 1 m³ | Base unit | – |
4. Metric Units – Capacity
| Unit | Relation | Conversion |
|---|---|---|
| 1 ml | 1 cm³ | 1000 ml = 1 l |
| 1 l | 1000 cm³ | 1 m³ = 1000 l |
5. Metric Units – Mass
| Unit | Relation to kg | Conversion |
|---|---|---|
| 1 g | 1/1000 kg | 1000 g = 1 kg |
| 1 kg | Base unit | – |
| 1 tonne (t) | 1000 kg | 1 kg = 0.001 t |
6. Key Conversion Principles
- For area: square the length conversion factor.
- Example: 1 m = 100 cm → 1 m² = 100² = 10,000 cm².
- For volume: cube the length conversion factor.
- Example: 1 m = 100 cm → 1 m³ = 100³ = 1,000,000 cm³.
- For capacity: 1 litre = 1000 cm³.
7. Quick Reference Table
| Conversion | Factor |
|---|---|
| mm → cm | ÷ 10 |
| cm → m | ÷ 100 |
| m → km | ÷ 1000 |
| cm² → m² | ÷ 10,000 |
| m² → cm² | × 10,000 |
| cm³ → m³ | ÷ 1,000,000 |
| m³ → cm³ | × 1,000,000 |
| litres → m³ | ÷ 1000 |
| m³ → litres | × 1000 |