Multiple choice general knowledge math & puzzles

How many diameters does a circle of radius 10 cm have?

  1. 1

  2. 5

  3. 20

  4. Infinite
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D Correct answer
Explanation

A circle has infinite diameters because any line passing through the center to any point on the circumference is a diameter. Since there are infinite points on a circle's circumference, there are infinite possible diameters. This is a fundamental property of circles.

AI explanation

A diameter is any straight line segment passing through the center of the circle with both endpoints on the circle. Since a circle has infinitely many lines through its center (one for every angle from 0 to 180 degrees), it has infinitely many diameters, not just one. The radius (10 cm) is irrelevant to the count -- it only affects the diameter's length (20 cm), not how many diameters exist. Options 1, 5, and 20 confuse 'diameter' as a single fixed line with the concept of the geometric locus of all such lines.

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