To compare \( \sqrt{42} \) and \( \sqrt{58} \), we can calculate their approximate values.
1. **Calculate \( \sqrt{42} \):**
- Since \( 6^2 = 36 \) and \( 7^2 = 49 \), we know that \( \sqrt{42} \) is between 6 and 7.
- A better approximation can be found using a calculator, giving us:
\[
\sqrt{42} \approx 6.48
\]
2. **Calculate \( \sqrt{58} \):**
- Similarly, since \( 7^2 = 49 \) and \( 8^2 = 64 \), we know that \( \sqrt{58} \) is between 7 and 8.
- Using a calculator, we find:
\[
\sqrt{58} \approx 7.62
\]
3. **Finding the approximate difference:**
- Now, we compute the difference between the two values:
\[
\sqrt{58} - \sqrt{42} \approx 7.62 - 6.48 = 1.14
\]
To express this difference in tenths, we can round \( 1.14 \) to the nearest tenth:
The approximate difference in tenths between \( \sqrt{58} \) and \( \sqrt{42} \) is \( \boxed{1.1} \).