Decagon how many sides does it have

There are three possible classifications of decagon that are given below:. A regular decagon is a polygon along with10 equal sides and 10 vertices. The sides and angles are congruent in a regular decagon. The characteristics of a regular decagon are:. An irregular decagon does not have equal sides and angles. At least two sides and angles are different in measurement. Look at the images given below showing irregular decagons. Like any other polygon, decagons also can be convex and concave.

While concave decagons have indentations a deep recess. Simple decagons refer to decagons with no sides crossing themselves. They follow all of the above said regular decagon rules.

While complex decagons refer to decagons that are self-intersecting and have additional interior spaces. They do not strictly follow any prescribed rules of decagons regarding their interior angles and their sums. To find the sum of the interior angles of a decagon, first, divide it into triangles. There are eight triangles in a regular decagon. 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. 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.

Remember to name all the attributes, in case a shape fits more than one category. Now that you have studied this lesson, you are able to recognize and define a decagon, state the identifying properties of all decagons, and the identifying properties of regular decagons. You are also able to identify as decagons the stars on the U. Ratios and Proportions. Get better grades with tutoring from top-rated professional tutors. Get help fast. Want to see the math tutors near you?

A decagon is a sided polygon, with 10 interior angles, and 10 vertices which is where the sides meet. That is not the case with the next category of decagons: complex. Instructor: Malcolm M. Malcolm has a Master's Degree in education and holds four teaching certificates. He has been a public school teacher for 27 years, including 15 years as a mathematics teacher.

Regular Decagon In geometry, a decagon is a ten-sided polygon or gon.