JAMB - Mathematics (1990 - No. 29)
Each of the interior angles of a regular polygon is 140°. How many sides has the polygon?
9
8
7
5
Explication
For a regular polygon of n sides
n = \(\frac{360}{\text{Exterior angle}}\)
Exterior < = 180° - 140°
= 40°
n = \(\frac{360}{40}\)
= 9 sides
n = \(\frac{360}{\text{Exterior angle}}\)
Exterior < = 180° - 140°
= 40°
n = \(\frac{360}{40}\)
= 9 sides