## Decagon

### A decagon is a polygon that has ten sides and ten angles

A decagon is a polygon that has ten sides and ten angles. The word “decagon” is derived from the Latin words “decem” meaning “ten” and “gonia” meaning “angle”. Each angle in a decagon measures 144 degrees, as given by the formula: (n-2) * 180 / n, where n is the number of sides of the polygon. So for a decagon, it is (10-2) * 180 / 10 = 144 degrees.

A decagon can also be classified as a regular or irregular decagon. A regular decagon has congruent sides and angles, meaning all the sides and angles are equal in length and measure respectively. An irregular decagon has sides and angles of different lengths and measures.

To find the perimeter of a decagon, you simply add the lengths of all its sides. If all sides are equal, as in a regular decagon, you can multiply the length of one side by ten to get the perimeter. If it’s an irregular decagon, you would need to know the lengths of all the sides.

The area of a decagon can be calculated using various methods, one of which involves dividing the decagon into smaller shapes. For example, you can divide it into ten isosceles triangles, each with a central angle of 36 degrees (360 degrees divided by 10 sides). Then, using trigonometric functions or special properties of isosceles triangles, you can find the area of each triangle and sum them up to find the total area of the decagon.

Remember to always include units when providing answers for perimeter or area (e.g., cm, meters, etc.).

##### More Answers:

The Importance of the Incenter in Triangles | Properties and Uses for Geometric Proofs and ConstructionUnderstanding the Circumcenter of a Triangle | Definition, Calculation Methods, and Properties

Finding the Incenter of a Triangle | Steps and Importance of the Incenter and Incircle