What is the sum of the interior angles of a hendecagon?

1 Answer
Dec 19, 2015

Sum of interior angles of a hendecagon #=1620^@#

Explanation:

The real issue here is knowing that a "hendecagon" is an #11# sided (and angled) polygon.

The formula for the sum of the interior angles of an #n#-gon is
#color(white)("XXX")180^@xx(n-2)color(white)("XXXXX")#provided #n>=3#

An #11#-gon (hendecagon) can be divided into #9# triangles by connecting vertices; each triangle has an interior angle sum of #180^@#

Sum of interior angles of hendecagon #=180^@ xx 9 = 1620^@#