MATHEMATICS

JAMB 2001 - Question 21

Mathematics 2001 JAMB Past Questions - Question 21: Find the number of sides of regular polygon whose interior angle is twice the exterior angle .

Find the number of sides of regular polygon whose interior angle is twice the exterior angle .
A:
B:
C:
D:
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Correct Answer

C

Explanation

Let's denote the number of sides of the regular polygon as n.The sum of the interior angles of a polygon with n sides is given by the formula (n-2) * 180 degrees.The measure of each interior angle of a regular polygon is given by the formula (n-2) * 180 degrees / n.The measure of each exterior angle of a regular polygon is given by the formula 360 degrees / n.According to the given condition, the interior angle is twice the exterior angle. So we can write the equation:(n-2) * 180 degrees / n = 2 * (360 degrees / n)To simplify the equation, we can cross-multiply:(n-2) * 180 degrees = 2 * 360 degrees180n - 360 = 720180n = 1080n = 1080 / 180n = 6Therefore, the regular polygon has 6 sides.