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

Dodecagon classifications

Like various other polygons, a dodecagon have the right to be classified as constant or irregular.

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Regular dodecagonIrregular dodecagon
All sides and also interior angles space 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 type of two points on its boundary lies outside of it. No one of the inner angles is greater than 180°. Think of a convex dodecagon together bulging outwards, such as the continuous dodecagon pictured above.

Conversely, a concave dodecagon, favor the irregular dodecagon presented above, has at least one heat segment that deserve to be drawn between points ~ above its boundary however lies outside of it. Also, at least one that its interior angles is higher than 180°.

A convex dodecagon walk not have to be a continual dodecagon. Yet, a consistent dodecagon is always a convex dodecagon. The dodecagon below is convex but plainly has sides and also angles that space not congruent. This dodecagon is irregular.


Angles the a dodecagon

Dodecagons can be damaged into a series of triangle by diagonals attracted from that vertices. This series of triangles have the right to be supplied to discover the sum of the internal angles that the dodecagon.

Diagonals are attracted from peak A in the convex dodecagon below, creating 10 triangles. Similarly, 10 triangles can also be attracted in a concave dodecagon. Since the sum of the degrees in a triangle is 180°, the amount of the inner angles the a dodecagon is 10 × 180° = 1800°.

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A consistent dodecagon has actually equal interior angle measures. Because 1800°/12 = 150°, each interior angle in a continual dodecagon has a measure up of 150°. Also, each exterior angle has a measure of 30° since the exterior angle and also interior angle form a directly angle.