This article deals with the definition and the facts of the polygons.The polygons are closed two-dimensional figure made up of three or more than three **line segments**. on
basic of the side, the polygon are classified as follows

They clssify the polygons are,

1. Triangle (three sides)

2. Quadrilateral (four sides)

3. Pentagon (five sides)

4. Hexagon (six sides)

5. Heptagon (seven sides)

6. Octagon (eight sides)

7. Nonagon (nine sides)

8. Decagon (ten sides)

**Fact about Triangle**

- It is the three-sided polygon
- Total Interior angle of the triangle is 180 degrees.
- Total Exterior angle of the triangle is 360degrees.
- Each Interior angle is 60 degrees
- Each exterior angle is 120 degrees

**Fact about Quadrilaterals**

- It is the four -sided polygon
- Total Interior angle of the triangle is 360 degrees.
- Total Exterior angle of the triangle is 360degrees.
- Each Interior angle is 90 degrees
- Each exterior angle is 90 degrees

**Fact about pentagon**

- It is the five -sided polygon
- Total Interior angle of the triangle is 540degrees.
- Total Exterior angle of the triangle is 360degrees.
- Each Interior angle is 108 degrees
- Each exterior angle is 72 degrees

**Fact about hexagon**

- It is the six -sided polygon
- Total Interior angle of the triangle is 720 degrees.
- Total Exterior angle of the triangle is 360degrees.
- Each Interior angle is 120 degrees
- Each exterior angle is 60degrees

**Fact about octagon**

- It is the 8 -sided polygon
- Total Interior angle of the triangle is 1080 degrees.
- Total Exterior angle of the triangle is 360degrees.
- Each Interior angle is 135 degrees
- Each exterior angle is 45 degrees

**Problem 1:**

**Find the Interior angle of pentagon using the formula.**

**Solution:**

The angle that formed inside the pentagon is said to be interior angle of the pentagon

Formula for calculating the interior angle of the regular polygons:

**Sum of Interior angle of the regular polygons = (n-2) 180 degrees**

Here n is the number of the polygon.

Here it is pentagon, n=5

**Sum of Interior angle of the pentagon polygon = (5-2) 180 degrees**

= (3) (180)

= 540 degrees.