Square sizes: each step is times 100
You learn to convert square units, like m² to dm² and hectares to m², where each step is times 100.
How to work it out
- Check whether there is a ² next to the unit, or whether it is about hectares and ares.
- Count the steps between the two units.
- If you go down, multiply by 100 for each step.
- If you go up, divide by 100 for each step.
A worked example
3 m² = ? cm²
- Find the units on the ladder: from m² to cm².
- Count the steps: m², dm², cm², so 2 steps down.
- Multiply by 100 for each step: 3 × 100 × 100 = 30,000.
- It is 30,000 cm².
More examples
500 cm² = ? dm²
- From cm² to dm² is 1 step up.
- Divide by 100: 500 ÷ 100 = 5.
- It is 5 dm².
3 ha = ? a
- From ha to a is 1 step down.
- Multiply by 100: 3 × 100 = 300.
- It is 300 a.
2 ha = ? m²
- From ha to m² is 2 steps down: ha, a, m².
- Multiply by 100 for each step: 2 × 100 × 100 = 20,000.
- It is 20,000 m².
Try it yourself
From square kilometre to square hectometre
7 km² = ? hm²
From square decimetre to square metre
250 dm² = ? m²
Watch out
You multiply by 10, as with ordinary units of length: 2 m² becomes 20 dm².
If there is a ² next to the unit, each step is times 100.
From ha to m² you multiply by 100 only once.
The are comes between ha and m². That is 2 steps, so multiply by 100 and then by 100 again.
Tips
- An are is 10 by 10 metres, so 100 m². A hectare is 100 by 100 metres.
- Write the ² next to it: an area is always in square units.
Why it works
A square metre is a square 10 dm long and 10 dm wide. 10 × 10 = 100 square decimetres fit inside it. So with square units each step is not 10 but 100. An are is 10 by 10 metres (100 m²) and a hectare is 100 are, so there too each step is times 100.