Is it possible to have a regular polygon each of whose exterior angles is 50°?

Each exterior angle of an $n$-sided polygon $=\left(\frac{360}{n}\right)^{\circ}$

If the exterior angle is $50^{\circ}$, then:

$\frac{360}{n}=50$

$\Rightarrow n=7.2$

Since n is not an integer, we cannot have a polygon with each exterior angle equal to 50°.