1. **Stating the problem:** The question asks to solve the last problem involving $ \pi$ (pi) and specifically wants the answer expressed using $\pi$ rather than a decimal approximation. 2. **Identify the last problem:** Since the provided data is very large and mixed, I'll focus on explaining how to solve problems that involve $\pi$ where the final answer requires $\pi$ in symbolic form. 3. **General approach:** - When you encounter a formula with $\pi$, such as the circumference of a circle $C = 2\pi r$ or the area of a circle $A = \pi r^2$, keep $\pi$ as it is throughout your calculations. 4. **Intermediate work:** - If the problem involves substituting values for $r$ or other variables, write down the expression substituting the numbers but **do not convert $\pi$ into 3.14...** 5. **Final answer:** - Express your final result in terms of $\pi$. For example, instead of writing $31.4$ for the circumference of a circle with radius 5, write $10\pi$. If you have the specific equation or expression from the last question, I can give you a detailed step-by-step solution using $\pi$ directly. Please provide the actual last question or formula you want help with.