Multiple choice general knowledge math & puzzles

What is the “formal” definition of pi?

  1. the surface area of a sphere of diameter 22/7

  2. 3.1415926

  3. the ratio of a circle’s diameter to its circumference.

  4. the ratio of a circle’s circumference to its diameter

  5. the ratio of a circle’s circumference to its radius.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The formal mathematical definition of pi is the ratio of a circle's circumference (C) to its diameter (D), written as pi = C/D. Option C incorrectly reverses this ratio (diameter to circumference would give 1/pi), while option E incorrectly uses radius instead of diameter (C/radius would equal 2pi, not pi). Option B is only a decimal approximation.

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