<Tr> <Th> Dual polygon </Th> <Td> Self </Td> </Tr> <Tr> <Th> Properties </Th> <Td> Convex, cyclic, equilateral, isogonal, isotoxal </Td> </Tr> <P> In geometry, an icosagon or 20 - gon is a twenty - sided polygon . The sum of any icosagon's interior angles is 3240 degrees . </P> <P> The regular icosagon has Schläfli symbol (20), and can also be constructed as a truncated decagon, t (10), or a twice - truncated pentagon, tt (5). </P>

What is the sum of the interior angles of an icosagon