It is a triangle
Heptagon
Icosogon
A pentagon
Hexagon
It is an 11 sided polgon
A hexagon is a six sided polygon but not necessarily you can hve other six sided figures
But it is because an 11 sided polgon is called an undecagon
An hexagon is a 6 sided polygon that can be regular or irregular
It wil be a regular 18 sided polgon
The name of the angle which has three sided polygon called Triangle.
'What_is_the_longest_side_of_a_right_angle_triangle_called
That might be a figure as simple as a triangle, as long as it is no special triangle (that is, a triangle with sides of three different lengths).