A dodecagon is a polygon with 12 sides and 12 vertices. "Do-" method "two" and "deca-" way "ten."

Dodecagon classifications

Like other polygons, a dodecagon have the right to be divide as consistent 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 as convex or concave.

A convex dodecagon is a polygon whereby no heat segment between any kind of two point out on its border lies outside of it. Nobody of the internal angles is better than 180°. Think the a convex dodecagon as bulging outwards, such together the continual dodecagon pictured above.

Conversely, a concave dodecagon, choose the rarely often rare dodecagon displayed above, contends least one line segment that can be drawn between points on its boundary however lies outside of it. Also, at least one the its inner angles is greater than 180°.

A convex dodecagon does not need to be a constant dodecagon. Yet, a consistent dodecagon is constantly a convex dodecagon. The dodecagon below is convex but clearly has sides and also angles that space not congruent. This dodecagon is irregular.


Angles of a dodecagon

Dodecagons can be broken into a collection of triangle by diagonals attracted from its vertices. This collection of triangles deserve to be offered to find the sum of the inner angles the the dodecagon.

Diagonals are attracted from vertex A in the convex dodecagon below, creating 10 triangles. Similarly, 10 triangle can likewise be attracted in a concave dodecagon. Because the sum of the levels in a triangle is 180°, the sum of the interior angles of a dodecagon is 10 × 180° = 1800°.

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A constant dodecagon has actually equal internal angle measures. Due to the fact that 1800°/12 = 150°, each internal angle in a continuous dodecagon has a measure up of 150°. Also, every exterior angle has a measure of 30° because the exterior angle and interior angle kind a straight angle.