The question asks for the circumference of a circle, given the diameter $d = 8 \, \text{in.}$.

Formula for Circumference:

$C = \pi \cdot d$

Substituting $d = 8$:

$C = \pi \cdot 8 = 8\pi \, \text{in.}$

Answer:

The circumference of the tree's ring is: $\boxed{8\pi \, \text{in.}}$

Would you like a breakdown of the steps or have any questions?

Here are 5 related questions to expand your understanding:

1. What is the formula for the circumference in terms of the radius?
2. If the radius was given instead of the diameter, how would you calculate the circumference?
3. How does the value of $\pi$ affect the circumference of a circle?
4. What is the relationship between the diameter and the radius of a circle?
5. How can you approximate the circumference using $\pi \approx 3.14$?

Tip: Always double-check whether you're working with the diameter or the radius when solving circle-related problems.