A rectangular polygon of (2k + 1) sides has 140o as the size of each interior angle. Find k

A rectangular polygon of (2k + 1) sides has 140o as the size of each interior angle. Find k

Answer Details

A rectangular has all sides and all angles equal. If each interior angle is 140o each exterior angle must be
180o - 140o = 40o
The number of sides must be $\frac{{360}^o}{{40}^o}$ = 9 sides
hence 2k + 1 = 9
2k = 9 - 1
8 = 2k
k = $\frac{8}{2}$
= 4