What is an 11 and 12 sided shape called?

Hint: We are required to find the names for 11 and 12 sided shapes. Firstly, we draw a polygon of 11 sides and label the points. Then, draw the polygon of 12 sides and label the points to get the desired result.

Complete step-by-step answer:
A polygon, in mathematics, is a geometric figure that has a finite number of sides. The sides of any polygon are line segments connected at either end. The point of intersection of two or more points is called the vertex or the corner of the polygon.
The word polygon is composed of two words ‘poly’ meaning many and ‘gon’ meaning sides.
Examples of polygons:
1. Triangle

The triangle is a polygon because it has three sides and three angles.
2. Square

The square is a polygon because it has four sides and four angles.
In geometry, the shape with 11 sided shape is called a hendecagon. It is also called as undecagon and endecagon.
Hendecagon is a polygon that is made up of 11 sides and 11 angles.
The sum of internal angles of a hendecagon is ${{120}^{\circ }}$
The perimeter of the 11 sided shape is the product of 11 and side length.
The hendecagon is diagrammatically represented as follows,

From the above figure,
We can conclude that the figure has 11 vertices namely,
Vertices: A, B, C, D, E, F, G, H, I, J, K.
We can conclude that the figure has 11 edges namely,
Edges: AB,BC, CD, DE, EF, FG, GH, HI, IJ, JK, KA
In geometry, the shape with 12 sided shape is called a dodecagon.
Dodecagon is a polygon that is made up of 12 sides and 12 angles.
The sum of internal angles of a hendecagon is ${{150}^{\circ }}$
The perimeter of the 11 sided shape is the product of 12 and side length.
The Dodecagon is diagrammatically represented as follows,
From the above figure,
We can conclude that the figure has 11 vertices namely,
Vertices: A, B, C, D, E, F, G, H, I, J, K, L.
We can conclude that the figure has 11 edges namely,
Edges: AB,BC, CD, DE, EF, FG, GH, HI, IJ, JK, KL, LA.
$\therefore $ 11 sided and 12 sided polygons are called Hendecagon and Dodecagon respectively.

Note: Any polygon is always a closed figure. We must take care of what the figure might look like and not forget to label the vertices while drawing a polygon. A circle is not a polygon because it is curved and not formed from line segments.