Electrical mathQuestion 802 of 1506

What is the ratio of square mils to circular mils?

  1. 1 square mil for every 1 circular mil
  2. 2 square mils for every 3 circular mils
  3. π square mils for every 4 circular mils
  4. 4 square mils for every π circular mils
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Correct answer: π square mils for every 4 circular mils

A circular mil is a smaller area than a square mil, by the ratio π/4.

Source: Lessons in Electric Circuits I: DC (Kuphaldt), 12.2: Conductor Size

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Questions last reviewed: 18 October 2026