# Hendecagon

Hendecagon

In geometry, a hendecagon (also undecagon [ [http://www.mathopenref.com/undecagon.html Undecagon Definition - Math Open Reference] ] ) is an 11-sided polygon. The name "undecagon" is often seen as incorrect, but the matter is up for debate. The prefix should be the Greek 'hen', not the Latin 'un' (which is also of Greek origin) [ [http://mathworld.wolfram.com/Hendecagon.html Hendecagon - from Wolfram MathWorld ] ] . A hendecagon has 11 sides.A regular hendecagon has internal angles of 147.272727... degrees.The area of a regular hendecagon with side length "a" is given by:$A = frac\left\{11\right\}\left\{4\right\}a^2 cot frac\left\{pi\right\}\left\{11\right\} simeq 9.36564,a^2.$A regular hendecagon is not constructible with compass and straightedge.

Use in coinage

The Canadian dollar coin, the loonie, is patterned on a regular hendecagonal prism, as is the Indian two-rupee coin.

It was also patterned on the Susan B. Anthony dollar of the United States from 1979-1981 and again in 1999.

ee also

*Hendecagram

References

External links

* [http://www.mathopenref.com/undecagon.html Properties of an Undecagon (hendecagon)] With interactive animation
*

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### Look at other dictionaries:

• Hendecagon — Hen*dec a*gon, n. [Gr. ? eleven + ? angle: cf. F. hend[ e]cagone.] (Geom.) A plane figure of eleven sides and eleven angles. [Written also {endecagon}.] [1913 Webster] …   The Collaborative International Dictionary of English

• hendecagon — [hen dek′ə gän΄] n. [Fr hendécagone: see HENDECA & GON] a plane figure with eleven angles and eleven sides hendecagonal [hen΄di kag′ə nəl] adj …   English World dictionary

• hendecagon — hendecagonal /hen deuh kag euh nl/, adj. /hen dek euh gon /, n. a polygon having 11 angles and 11 sides. [1695 1705; HENDECA + GON] * * * …   Universalium

• hendecagon — noun a polygon with eleven edges and eleven angles. Syn: undecagon See Also: hendecagonal …   Wiktionary

• hendecagon — n. eleven sided figure with eleven angles …   English contemporary dictionary

• hendecagon — [hɛn dɛkəg(ə)n] noun a plane figure with eleven straight sides and angles. Derivatives hendecagonal ˌhɛndɪ kag(ə)n(ə)l adjective …   English new terms dictionary

• hendecagon — /hɛnˈdɛkəgən/ (say hen dekuhguhn) noun a polygon having eleven angles and eleven sides. {Greek hendeka eleven + gon} –hendecagonal /hɛndəˈkægənəl/ (say henduh kaguhnuhl), adjective …

• hendecagon —   n. 11 sided plane figure.    ♦ hendecahedron, n. 11 sided solid figure.    ♦ hendecasyllable, n. verse line of 11 syllables …   Dictionary of difficult words

• hendecagon — n. a plane figure with eleven sides and angles …   Useful english dictionary

• endecagon — Hendecagon Hen*dec a*gon, n. [Gr. ? eleven + ? angle: cf. F. hend[ e]cagone.] (Geom.) A plane figure of eleven sides and eleven angles. [Written also {endecagon}.] [1913 Webster] …   The Collaborative International Dictionary of English

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