<Tr> <Th> Dual polygon </Th> <Td> Self </Td> </Tr> <Tr> <Th> Properties </Th> <Td> Convex, cyclic, equilateral, isogonal, isotoxal </Td> </Tr> <P> In geometry, a decagon is a ten - sided polygon or 10 - gon . </P> <P> A regular decagon has all sides of equal length and each internal angle will always be equal to 144 ° . Its Schläfli symbol is (10) and can also be constructed as a truncated pentagon, t (5), a quasiregular decagon alternating two types of edges . </P>

What do you call a ten sided shape