Heptagon

Regular heptagon
A regular heptagon
Teep	Regular polygon
Edges an vertices	7
Schläfli seembol	{7}
Coxeter diagram
Symmetry group	Dihedral (Dih7), order 2×7
Internal angle (degrees)	$\approx 128.571$°
Dual polygon	self
Properties	convex, cyclic, equilateral, isogonal, isotoxal

In geometry, a heptagon is a polygon wi seven sides an seven angles. In a regular heptagon, in which aw sides an aw angles are equal, the sides meet at an angle o 5π/7 radians, 128.5714286 degrees. Its Schläfli seembol is {7}. The aurie (A) o a regular heptagon o side length a is gien bi

$A={\frac {7}{4}}a^{2}\cot {\frac {\pi }{7}}\simeq 3.633912444a^{2}.$

The heptagon is an aa occasionally referred tae as the septagon, uisin "sept-" (an elision o septua-, a Laitin-derived numerical prefix, rather nor hepta-, a Greek-derived numerical prefix) thegither wi the Greek suffix "-agon" meanin angle).