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WAEC Mathematics 1991 (August) Question 45

Question 45

Angles and Polygons

In a given regular polygon, the ratio of the exterior angle to the interior angles is 1 : 3. How many side has the polygon?

  1. A.4
  2. B.5
  3. C.6
  4. D.8
  5. E.12
Show the answer and explanation

Answer: D (8)

Explanation

Exterior + interior = 180°, so the exterior angle = 180° ÷ 4 = 45°. Number of sides = 360° ÷ 45° = 8.