Introduction:

In geometry a **polygon** is traditionally a plane figure that is bounded by a closed path or circuit, composed of a finite sequence of straight line segments. These segments are called its edges or sides, and the points where two edges meet are the polygon's vertices or corners. The interior of the polygon is sometimes called its body. **(Source– Wikipedia). **The name of the each polygon will vary by its number of sides.** **In this article we shall see the list of all polygons and its names.

List of all polygon shapes:

The below list shows the name of the all polygon, number of sides and its internal angles.

**Number of sides** **polygon name ** **Internal angles **

** 3 **Triangle 60°

4 Square or Quadrilateral 90°

5 Pentagon 108°

6 Hexagon 120°

7 Heptagon 128.571°

8 Octagon 135°

9 Nonagon or Ennagon 140°

10 Decagon 144°

11 Hendecagon or Undecagon 147.273°

12 Dodecagon 150°

13 Triskaidecagon 152.308°

14 Tetrakaidecagon 154.286°

15 Pendedecagon 156°

16 Hexdecagon 157.5°

17 Heptdecagon 158.824°

18 Octdecagon 160°

19 Enneadecagon 161.053°

20 Icosagon 162°

30 Triacontagon 168°

40 Tetracontagon 171°

50 Pentacontagon 172.8°

60 Hexacontagon 174°

70 Heptacontagon 174.857°

80 Octacontagon 175.5°

90 Enneacontagon 176°

100 Hectagon 176.4°

1000 Chiliagon 179.640°

10000 Myriagon 179.964°

We shall discus about basic some polygon shapes.

**Triangle:**

** **Triangleis a three sided regular polygons. Its all three sides and three internal angles are equal. The sum of its internal angles is 180^{0}. the diagram of triangle is shown in below.

**Formula:**

**Area of equilateral triangle (A) =a ^{2} x `sqrt(3)/4` square units**

** a – side length**

**Perimeter of equilateral triangle (P) = a + a + a units**

** = 3 a**

** a – side length**

** Square or quadrilateral:**

** **The square is a four sided regular polygon. Its all four sides and four internal angles are equal. The internal angles are 90^{0}. The sum of internal angle of square is 360^{0}. The diagram of square is shown in below.

**Formula:**

**Area of square, A = a ^{2}**

^{ } a – side length

**Perimeter of the square, P = 4a units **

**Pentagon:**

** **It is a five sided regular polygon. Its all five sides are equal. Its each five internal is 108^{0}. The sum of internal angles is 540^{0}. The diagram of pentagon is shown in below.

** Formula:**

**Area of the pentagon (A) = 1.72 a ^{2} square units **

** a - side length**

** Perimeter of the pentagon (P) = 5a units **

** Hexagon: **

** ** It is a six sided regular polygon. Its all has six sides and six internal angles are equal. Its each internal angle is 120^{0}. The sum all internal angles is 720^{0}. The diagram of hexagon is shown in figure.

**Formula:**

**Area of the pentagon (A) = 2.6 a ^{2} square units **

** a - side length **

** Perimeter of the pentagon (P) = 6a units **