Unit conversion check (fractional inches → millimeters) Using a standard fractional–decimal–metric chart (or by direct calculation), what is the metric equivalent in millimeters of 3/16 inch, rounded to four decimal places?
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A1.906
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B4.7625
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C5.958
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D14.6844
Answer
Correct Answer: 4.7625
Explanation
Introduction / Context:Mechanical drawings often require converting legacy imperial measurements to metric for tooling or international suppliers. Converting fractional inches to millimeters is straightforward with the inch-to-millimeter factor of 25.4.
Given Data / Assumptions:
- Target value: 3/16 inch.
- Exact conversion: 1 inch = 25.4 mm (by definition).
- Desired output: millimeters to four decimal places when appropriate.
Concept / Approach:First convert the fraction to a decimal inch value, then multiply by 25.4 to get millimeters. Keep sufficient precision during intermediate steps.
Step-by-Step Solution:
Convert 3/16 to decimal inches: 3 / 16 = 0.1875 inch.Multiply by the exact factor: mm = 0.1875 * 25.4.Compute: 0.1875 * 25.4 = 4.7625 mm.Round/format as needed: 4.7625 mm already has four decimal places.Verification / Alternative check:Consult a standard conversion chart: line for 3/16 inch lists 0.1875 inch and 4.7625 mm, confirming the arithmetic.
Why Other Options Are Wrong:
- 1.906 mm: Approximately 3/64 inch, not 3/16 inch.
- 5.958 mm: Does not correspond to a common simple fraction; too large for 3/16.
- 14.6844 mm: Roughly 37/64 inch; far larger than 3/16.
Common Pitfalls:Confusing numerator/denominator or using 25 instead of 25.4 leads to significant error. Always retain sufficient precision before rounding.
Final Answer:4.7625