To find a rational number with one decimal place that is between \( \sqrt{17} \) and \( \sqrt{18} \), we first need to calculate the approximate values of these square roots.
Calculating the square roots:
- \( \sqrt{17} \) is approximately \( 4.123 \).
- \( \sqrt{18} \) is approximately \( 4.243 \).
Now, we want a rational number with one decimal place that lies between these two values. The rational numbers with one decimal place between \( 4.123 \) and \( 4.243 \) are:
- \( 4.2 \)
Thus, \( 4.2 \) is a rational number with one decimal place that is between \( \sqrt{17} \) and \( \sqrt{18} \).