A dodecagon is a polygon through 12 sides and 12 vertices. "Do-" means "two" and "deca-" means "ten."

Dodecagon classifications

Like various other polygons, a dodecagon can be divide as regular or irregular.

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Regular dodecagonIrregular dodecagon
All sides and interior angles room congruentSides and angles have actually various lengths

A dodecagon can likewise be classified together convex or concave.

A convex dodecagon is a polygon whereby no line segment between any two points on its border lies outside of it. Nobody of the inner angles is greater than 180°. Think that a convex dodecagon together bulging outwards, such together the regular dodecagon pictured above.

Conversely, a concave dodecagon, like the rarely often, rarely dodecagon presented above, has at least one heat segment that have the right to be drawn between points ~ above its boundary yet lies exterior of it. Also, at least one the its internal angles is higher than 180°.

A convex dodecagon go not need to be a continual dodecagon. Yet, a constant dodecagon is constantly a convex dodecagon. The dodecagon below is convex but plainly has sides and also angles that are not congruent. This dodecagon is irregular.


Angles the a dodecagon

Dodecagons deserve to be damaged into a collection of triangle by diagonals drawn from its vertices. This series of triangles have the right to be used to uncover the amount of the inner angles of the dodecagon.

Diagonals are attracted from crest A in the convex dodecagon below, forming 10 triangles. Similarly, 10 triangle can additionally be attracted in a concave dodecagon. Due to the fact that the sum of the degrees in a triangle is 180°, the sum of the interior angles the a dodecagon is 10 × 180° = 1800°.

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A constant dodecagon has equal internal angle measures. Because 1800°/12 = 150°, each internal angle in a regular dodecagon has actually a measure up of 150°. Also, each exterior angle has actually a measure of 30° since the exterior angle and interior angle form a right angle.