A nonagon is a polygon that has nine sides. In the figure below are several types of nonagons.
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Nonagon classifications
Like other polygons, a nonagon have the right to be classified as continual or irregular. If all the sides and also interior angles of a nonagon are equal, that is a continuous nonagon. Otherwise that is an rarely often, rarely nonagon.
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All sides and interior angles room equal | Not every sides and also angles space equal |
Nonagons and other polygons can additionally be classified together either convex or concave. If all inner angles of a nonagon are less than 180°, that is convex. If one or much more interior angle is larger than 180°, it is concave. A consistent nonagon is a convex nonagon.
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All inner angles 180° |
Diagonals that nonagon
A diagonal line is a line segment joining two non-consecutive vertices. A total of twenty-seven distinct diagonals deserve to be attracted for a nonagon. The following number is an example.

There are 6 diagonals extending from each of the 9 vertices of the nonagon above creating a full of 27 diagonals.
Internal angle of a nonagon
The amount of the interior angles of a nonagon amounts to 1260°.

As displayed in the number above, 6 diagonals deserve to be attracted to division the nonagon right into seven triangles. The blue lines over show just one way to divide the nonagon right into triangles; there are others. The amount of inner angles the the 7 triangles amounts to the sum of inner angles the the nonagon. Because the amount of the inner angles of a triangle is 180°, the sum of the internal angles the the nonagon is 9 × 180° = 1260°.
Regular nonagon
A continual nonagon is a nonagon in which every sides have actually equal length and all interior angles have equal measure.
Angles that a regular nonagon
Since every of the nine interior angles in a consistent nonagon room equal in measure, each inner angle actions 1260° ÷ 9 = 140°, as displayed below.

Each exterior edge of a continual nonagon has actually an same measure the 40°.

Symmetry in a constant nonagon
A continual nonagon has actually 9 currently of symmetry and also a rotational the opposite of stimulate 9, definition that it can be rotated in such a method that it will certainly look the same as the original shape 9 time in 360°.
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9 present of symmetry | Nine 40° of rotation around the center. |