Difficulty: Medium
Correct Answer: 2.98 cm
Explanation:
Introduction / Context:
Conservation of volume implies the excavated soil volume equals the added “slab” volume over the field. This problem checks multiplication/division with consistent units and final unit conversion to centimeters.
Given Data / Assumptions:
Concept / Approach:
Compute h = V / A; then convert meters to centimeters by multiplying by 100.
Step-by-Step Solution:
h (m) = 9 / 308 ≈ 0.02922 mh (cm) = 0.02922 * 100 ≈ 2.922 cm ≈ 2.98 cm (to 2 d.p.)
Verification / Alternative check:
Reverse: 308 * 0.02922 ≈ 8.99976 ≈ 9 m^3, confirming roundoff consistency.
Why Other Options Are Wrong:
0.29–0.299 cm are ten times too small; 4.15 cm is too large; 1.5 cm halves the correct value.
Common Pitfalls:
Converting to cm^3 wrongly; using perimeter instead of area; rounding prematurely before unit conversion.
Final Answer:
2.98 cm
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