To calculate the perimeter of the donkey's pen, we need the dimensions you referred to in part b. However, since the dimensions are not provided, I can guide you on how to calculate the perimeter if you have the specific values.
The formula for the perimeter \( P \) of a rectangular pen is:
\[ P = 2 \times (length + width) \]
If the dimensions are given (for example, let's say the length is \( l \) meters and the width is \( w \) meters), you would substitute those values into the formula.
For example, if the length is 24 meters and the width is 12 meters:
\[ P = 2 \times (24 + 12) = 2 \times 36 = 72 \text{ meters} \]
If you can provide the dimensions from part b, I can help you complete the calculation!