Find the number of sides of a regular polygon whose interior angle is twice the exterior angle.
A
6
B
2
C
3
D
8
Verified Correct Answer: A.
Step-by-Step Mathematical Solution
Let the ext. angle = x
Thus int. angle = 2x
But sum of int + ext = 180 (angle of a straight line).
2x + x = 180
3x = 180
x = 180/3 = 60
Each ext angle = 360/n
=> 60 = 360/n
n = 360/60 = 6
Source: Myschool Past Questions Archive (Record #1526)