For her phone service, Karen pays a monthly fee of $\$ 15$, and she pays an additional $\$ 0.04$ per minute of use. The least she has been charged in a month is $\$ 66.48$. What are the possible numbers of minutes she has used her phone in a month? Use $m$ for the number of minutes, and solve your inequality for $m$. \begin{tabular}{|c|c|c|c|} \hline 0 & \begin{tabular}{l} $\square<\square$ \\ $\square \geq \square$ \end{tabular} & $\square>\square$ & $\square \leq \square$ \\ \hline & $x$ & & 5 \\ \hline \end{tabular}

Step 1 ：The problem is asking for the number of minutes Karen could have used her phone in a month. We know that she pays a monthly fee of $15 and an additional $0.04 per minute of use. The least she has been charged in a month is $66.48.

Step 2 ：We can set up an inequality to represent this situation. The total cost is the monthly fee plus the cost per minute times the number of minutes. This total cost is at least $66.48. So, we have the inequality \(15 + 0.04m \geq 66.48\), where \(m\) is the number of minutes.

Step 3 ：We can solve this inequality for \(m\) to find the possible number of minutes she could have used her phone. The result indicates that the minimum number of minutes Karen could have used her phone in a month is 1287 minutes. This is because the least she has been charged in a month is $66.48, and she pays a monthly fee of $15 and an additional $0.04 per minute of use.

Step 4 ：Final Answer: The possible number of minutes Karen has used her phone in a month is \(m \geq \boxed{1287}\).