# A Closer Look at the Fascinating Decagon

A shape with 10 sides is called a decagon. It is a polygon, which means it is a two-dimensional figure with straight sides and angles. The word decagon comes from the Greek words “deka” meaning ten and “gonia” meaning angle. Each angle of a decagon measures 144 degrees, and the sum of all the angles is 1440 degrees.

One of the most interesting properties of a decagon is that it can be divided into 7 triangles. This is because the sum of the interior angles of any polygon with n sides is (n-2) x 180 degrees. Therefore, the sum of the interior angles of a decagon is (10-2) x 180 = 1440 degrees. Dividing this sum by the sum of the angles of a triangle (180 degrees) gives us the number of triangles that can be formed from a decagon, which is 8. However, one of these triangles is the decagon itself, leaving us with 7 distinct triangles.

Another interesting property of a decagon is that it has 35 diagonals. A diagonal is a line that connects two non-adjacent vertices, meaning two vertices that are not next to each other. To find the number of diagonals of a decagon, we can use the formula n(n-3)/2, where n is the number of sides. Therefore, the number of diagonals of a decagon is 10(10-3)/2 = 35.

A regular decagon is a decagon with all sides and angles equal. It is a symmetric shape that can be inscribed in a circle. The radius of this circle is known as the circumradius of the decagon, and it is equal to the distance from the center of the decagon to any of its vertices. The area of a regular decagon can be found using the formula (5/4) x s^2 x tan(π/10), where s is the length of one side.

A decagon is a fascinating shape with 10 sides, 144 degree angles, and 35 diagonals. It can be divided into 7 triangles and has a multitude of interesting properties. A regular decagon is an especialy beautiful shape that can be inscribed in a circle and has a well-defined circumradius and area formula.

## What Is A 11 Sided Shape Called?

An 11-sided shape is called a hendecagon, which is a polygon with 11 sides and 11 angles. The term “hendecagon” is derived from the Greek words “hendeka” meaning “eleven” and “gonia” meaning “angle”. It is also commonly referred to as an undecagon or unidecagon. The hendecagon is a unique and interesting geometric shape that has a variety of applications in mathematics, architecture, and art. Some notable examples of hendecagons in real life include the shape of some soccer balls, the exterior design of some buildings, and the shape of certain crystals.

## What Is A Shape With 12 Sides Called?

A shape with 12 sides is called a dodecagon. A dodecagon is a polygon with 12 straight sides and 12 angles. It is a two-dimensional shape that can be regular or irregular. A regular dodecagon has all sides of equal length and all angles of equal measure. It can be inscribed in a circle, with the vertices of the dodecagon lying on the circumference of the circle. The regular dodecagon is a type of regular polygon, which is a polygon with all sides and angles equal. Other examples of regular polygons include the equilateral triangle, square, pentagon, hexagon, and octagon.

## What Shape Has 20 Sides?

The shape that has 20 sides is called an icosahedron. It is a polyhedron, which means it is a three-dimensional shape with flat faces. The icosahedron has 20 faces, each of which is an equilateral triangle. It has 12 vertices, which are the points where the faces meet, and 30 edges, which are the lines where the faces intersect. The icosahedron is a regular polyhedron, meaning that all of its faces are congruent (identical) and all of its angles are equal. It is a common shape in mathematics and is often used in geometry and engineering applications.

## Conclusion

A shape with 10 sides is known as a decagon. It is a polygon that has 10 straight sides and 10 angles. A regular decagon is a decagon in whch all sides are of equal length and all angles are of equal measure. Decagons are fascinating shapes that can be found in nature and used in various man-made structures. They possess unique properties that make them useful in different applications, such as in geometry, architecture, and engineering. Understanding the properties and characteristics of a decagon is crucial in various fields, and it is essential for anyone seeking to have a comprehensive understanding of shapes and their applications.

William Armstrong

William Armstrong is a senior editor with H-O-M-E.org, where he writes on a wide variety of topics. He has also worked as a radio reporter and holds a degree from Moody College of Communication. William was born in Denton, TX and currently resides in Austin.