Decagon sides how many

We know that the number of sides of a decagon is To find the measure of the central angle of a regular decagon, we need to draw a circle in the middle. Divide this by ten, because a decagon has 10 sides. A diagonal is a line that can be drawn from one vertex to another. By joining one vertex to the remaining vertices of the decagon, 8 triangles will be formed. Look at the image given below, showing diagonals and triangles of a decagon.

Like other shapes, a regular decagon also has the formula to calculate perimeter and area. The formulas are mentioned below:. In the case of an irregular decagon, we can simply add the side lengths to find the perimeter.

Example 1 : Jenifer's hobby is collecting coins from various countries. She found a new coin to add to her collection.

Find out whether this coin resembles a decagon shape or not? Solution: Decagon has ten sides and ten angles. Therefore, the coin is not in a decagon shape as it only has 7 sides. A decagon can be recognized as a polygon with 10 sides, 10 interior angles, and 10 vertices. Decagon can be regular and irregular. Regular decagon has all equal sides. Irregular decagon has unequal sides.

If we know the measurement of the side length of a regular decagon, then we can use this formula to find the area. There is no formula to find the area of an irregular decagon, but we can divide it into triangles and try to find the area of all triangles and add them. According to the properties of a decagon, the total number of sides is 10 made by joining 10 vertices.

As there are only 10 sides and 10 vertices, therefore, the number of interiors and exteriors angles formed by all 10 sides are also A regular decagon has 10 vertices and 35 diagonals. The exterior angles of a decagon are the outside angles formed by two sides joined by one vertex of a decagon. Every exterior angle is adjacent to the corresponding interior angle and forms degrees at the vertex of the decagon.

In the regular decagon, all angles are equal. As the number of sides is 10 in a decagon. There is a formula to find the sum of interior angles of the n-sided polygon [ n-2 ] where n is equal to the number of sides. A decagon is known as a ten-sided shape or polygon with ten vertices and ten angles. When any shape is formed by joining 10 sides, it is called a decagon.

Learn Practice Download. Decagon In geometry, a decagon is known as a ten-sided polygon or ten-gon. What is a Decagon? Types of Decagon 3. Properties of Decagon 4. Decagon Formulas 5. Most of us, though, only encounter decagons in mathematics class and when feeling particularly patriotic. Decagons belong to the family of two-dimensional shapes called polygons.

Polygons get their name from Greek, meaning "many-angled," because all polygons have multiple interior angles. They close in a two-dimensional space using only straight sides. Drawing a decagon takes no skill; simply draw 10 line segments that connect, and you have it.

Drawing a concave decagon is actually fairly easy: make a five-pointed star and fill it in. That is the star that appears 50 times on our country's flag, and the outline of such a pentagram five-pointed star is a decagon. That means you see a lot of decagons anytime you are near our flag:.

Be careful to know the difference between the five-pointed pentagram the lines cross themselves and the decagon either just the outline of a pentagram or a solidly filled pentagram.

All polygons can be drawn as regular equal-length sides, equal-measure interior angles or irregular not restricted to congruent angles or sides. Because it is a challenging shape to make, the regular, convex decagon is popular with coins like those from Australia, Belize and Hong Kong.

Irregular decagons must simply have 10 sides closing in a space, but the lengths of their sides can vary greatly. Most polygons can be convex or concave. So far all the decagons discussed -- regular, irregular, concave, and convex -- share the same properties:. Decagons can be simple or complex. A simple decagon has no sides crossing themselves. A simple decagon follows all the conventional "rules" of polygons.

By contrast, a complex decagon is self-intersecting. In crossing its own sides, a complex decagon sets off additional interior spaces, but it is still said to have only 10 sides, 10 interior angles, and 10 vertices. Because it is so highly irregular and self-intersecting, a complex decagon need not follow any predictable rule about interior angles or their sums. Notice that a single decagon can fit into several categories. The classic regular decagon meets all these requirements:.

So, to be absolutely accurate and maybe a bit fussy you can describe this figure as a regular, convex, simple decagon:. Below are several decagons. See, without looking at the identifying information, if you can determine whether each is regular or irregular, convex or concave, simple or complex.