Step-by-step explanation:
the sum of all external angles in a polygon is 360°.
a single external angle is therefore 360/n °.
the sum of all internal angles is
(n - 2) × 180
a single internal angle is then
(n-2) × 180 / n
with n being the number of sides.
the internal and the external angle are together 180°.
so, we know
x + 29x = 180
30x = 180
x = 6°
360/n = x
360/x = n
360/6 = 60
so, this polygon has 60 sides.
