The image you've uploaded is about using formulas to solve problems involving the volume of a cylinder. Specifically, the exercise references a formula for the volume of a cylinder $V = \pi r^2 h$, where $r$ is the radius and $h$ is the height of the cylinder. Let's analyze and solve the problems you've provided:

Problem 1:

A student wants to use a radius of $0.25 \, \text{ft}$ in the formula $V = \pi r^2 h$ from the example. How would the rest of their work differ from the example?

In the example, the radius $r = 3 \, \text{inches}$ (converted from $24 \, \text{inches} \div 8$ cans = $3 \, \text{inches}$ per can). If the student uses $r = 0.25 \, \text{ft}$, which is equivalent to $3 \, \text{inches}$ (since $0.25 \, \text{ft} = 3 \, \text{inches}$), their process should be similar. The main difference would be in the units used and possibly any rounding differences.

Problem 2:

You are asked whether using $\pi$ or using 3 as an estimate for $\pi$ would provide a more exact calculation, and by how much.

Using $\pi \approx 3.14159$ would definitely be more exact than using 3. The reason for this is that $\pi$ is an irrational number with infinite decimal places, while 3 is just an approximation. The difference between $3.14159$ and 3 is about 0.14159, so the final answer using $\pi$ would be more accurate.

If you substitute $\pi = 3$, it will give a rougher estimate, and if you use $\pi$ with more decimal places (such as 3.14159), you would get a more precise height.

Would you like to go through detailed calculations for any of these questions? Let me know if you'd like further clarifications or have any other questions.

Here are five related questions to expand on this:

1. How do you convert between units when dealing with volume and area in different measurements (e.g., inches to feet)?
2. How does changing the radius of the cylinder affect its height when the volume is fixed?
3. Why is $\pi$ important in calculations involving circles and cylinders?
4. What happens to the volume if both the radius and height of a cylinder are doubled?
5. How does the approximation of $\pi$ (using 3 or 3.14) impact the precision of real-world measurements?

Tip: Always check your units carefully when solving problems, especially when switching between systems like inches and feet.