In this scenario, the dependent variable is the total cost charged by the photographer. It depends on the number of poses taken during the photo shoot. The total cost can be expressed with the formula:
\[ \text{Total Cost} = \text{Sitting Fee} + (\text{Cost per Pose} \times \text{Number of Poses}) \]
So in this case, as the number of poses increases, the total cost (dependent variable) will also increase.