To determine which statement is true using rational approximations, let's evaluate each expression:
-
\( \sqrt{81} > 9 \):
- \( \sqrt{81} = 9 \)
- This is false: \( \sqrt{81} = 9 \), so it is not greater than 9.
-
\( \sqrt{71} > \sqrt{61} \):
- The approximate values are \( \sqrt{71} \approx 8.426 \) and \( \sqrt{61} \approx 7.810 \).
- This is true: \( 8.426 > 7.810 \).
-
\( \sqrt{71} < \sqrt{61} \):
- This contradicts the previous statement where we found \( \sqrt{71} > \sqrt{61} \).
- This is false.
-
\( \sqrt{81} < 9 \):
- As stated earlier, \( \sqrt{81} = 9 \).
- This is also false: \( \sqrt{81} = 9 \), so it is not less than 9.
Based on the evaluations above, the only true statement is:
\( \sqrt{71} > \sqrt{61} \)