Four students made area conversions. Decide whether each statement is correct. Correct every statement that is false.
Use \(1\,\text{cm}^2=100\,\text{mm}^2\), \(1\,\text{m}^2=100\,\text{dm}^2\), \(1\,\text{yd}^2=9\,\text{ft}^2\), and \(1\) acre \(=43{,}560\,\text{ft}^2\).
a) \(2.4\,\text{cm}^2=24\,\text{mm}^2\)
b) \(7\,\text{m}^2=700\,\text{dm}^2\)
c) \(6\,\text{yd}^2=18\,\text{ft}^2\)
d) \(0.5\) acre \(=21{,}780\,\text{ft}^2\)
Hints
- Check each statement against the conversion relationship supplied for that pair of area units.
- Be alert to using a linear conversion factor where an area conversion factor is required.
- For the acre statement, think about what multiplying by one-half does to the full conversion amount.
Solution
1. Statement a is false. Since \(1\,\text{cm}^2=100\,\text{mm}^2\), \(2.4\times100=240\), so \(2.4\,\text{cm}^2=240\,\text{mm}^2\).
2. Statement b is correct because \(7\times100=700\).
3. Statement c is false. Since \(1\,\text{yd}^2=9\,\text{ft}^2\), \(6\times9=54\), so \(6\,\text{yd}^2=54\,\text{ft}^2\).
4. Statement d is correct because half of \(43{,}560\) is \(21{,}780\).
Answer
a) False; \(2.4\,\text{cm}^2=240\,\text{mm}^2\).
b) Correct.
c) False; \(6\,\text{yd}^2=54\,\text{ft}^2\).
d) Correct.