A decagon is a shape that has ten edges. DEC means TEN.
Any shape with straight edges can have perpendicular edges.
a circleA pedantic edit:Also an ellipse or a wriggly loop.Any shape that has no straight edges is described as a curvilinear shape.
Every shape that is round does not have edges. A shape that has sharp points and has straight lines can have edges.
Overall
An ellipse is a shape that could be described as looking like 'a squashed circle.' With no straight edges, this shape is also called an oval.
hexagon
An Octagon
A pentagon
hexagon
Polyhedra.
octagon !