Question

is it possible to have a regular polygon each whose interior angles is 100*

Answer 1

to find interior angle of any polygon
formula is 180(n-2) where n is number of sides
  so hexagon is of six sides
so 180 ( 6-2 )
  720 sum of all interior angles of hexagon
720/6 = 120
each interior angle is of 120
which is less than 100
so we can't have this type of hexagon

Answer 2

no as
each interior angle of regular hexagon  is of 120
which is greater than 100