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IKMC 2027 - Grades 11-12 - Self-study SET 7 - Thematic Batch 3 Question 20

IKMC · IKMC 2027 - Grades 11-12 - Self-study SET 7 - Thematic Batch 3

Question 20

On a circle of radius 1, points A,B,C,D,E,F are taken in clockwise order so that AB,BC,CD,DE,EF are respectively side lengths of inscribed regular polygons with 3,4,5,6,20 sides. How long is AF?

Editorial note: The original diagram is schematic. Use the stated regular-polygon side lengths rather than measuring the displayed separation of A and F.

Question illustration
  1. 1/π
  2. 1/(2π)
  3. π/(3 + 4 + 5 + 6 + 20)
  4. 1/[π(3 + 4 + 5 + 6 + 20)]
  5. A and F coincide