Question

The exterior angle of a regular polygon is one third of its interior angle. How many sides does polygon has?

A) 10

b) 8

c) 9

d) 13

Answer 1

Sum of exterior and interior angles is 180 deg.

If the interior angle is 3x, the exterior angle is x. Hence 3x+x = 4x = 180 or x = 45. The interior angle is 135 deg. So the polygon has 360/45 = 8 sides or it is a regular octagon
And the correct answer is (b)