Is it possible to have a regular polygon each of

Each interior angle of a regular polygon having $n$ sides $=180-\left(\frac{360}{n}\right)=\frac{180 n-360}{n}$

If each interior angle of the polygon is $100^{\circ}$, then:

$100=\frac{180 n-360}{n}$

$\Rightarrow 100 n=180 n-360$

$\Rightarrow 180 n-100 n=360$

$\Rightarrow 80 n=360$

$\Rightarrow n=\frac{360}{80}=4.5$

Since n is not an integer, it is not possible to have a regular polygon with each interior angle equal to 100°.