Step 1: Understanding the Question:
The question asks for the mathematical relationship between diameter ($d$) and girth (circumference, $G$) of a tree, assuming its cross-section is a perfect circle.
Step 2: Key Formula or Approach:
1. The formula for the circumference ($G$) of a circle is \( G = \pi \times d \).
2. To find $d$, we rearrange the formula: \( d = \frac{G}{\pi} \).
Step 3: Detailed Explanation:
• We know that \( \pi \approx 3.14159 \).
• Thus, \( d = \frac{1}{3.14159} \times G \).
• Let's calculate the value of $1/\pi$:
\[ \frac{1}{3.14159} \approx 0.3183 \]
• Rounding to four decimal places, we get the constant $0.3182$ or $0.3183$.
• Therefore, the relationship is \( d = 0.3182 \times G \).
• Conversely, \( G = \pi \times d \approx 3.14 \times d \), which is not listed as $3.182$ exactly in option D. Thus, B is the most standard conversion used in mensuration.
Step 4: Final Answer:
The relationship is given by the formula d = 0.3182 G.