what is the name for a 12 sided polygon
Dodecagon In geometry, a dodecagon or 12-gon is any twelve-sided polygon.
Octagon A regular octagon is a closed figure with sides of the same length and internal angles of the same size. It has eight lines of reflective symmetry and rotational symmetry of order 8. A regular octagon is represented by the Schläfli symbol {8}. The internal angle at each vertex of a regular octagon is 135° (    3 π 4   {\displaystyle \scriptstyle {\frac {3\pi }{4}}}  radians). The central angle is 45° (    π 4   {\displaystyle \scriptstyle {\frac {\pi }{4}}}  radians).