Question

Three valid names for an octagon

Answer 1

Remmeber that an octagon is a polygon formed by chain of 8 straight line segments.

The first valid name for a polygon of eight sides is octagon (from greek oktagonon, which means eight angles) 

The second valid name for a polygon of eight sides is eight-sided polygon.

The third valid name of a polygon of eight sides is 8-gon. After 6 sides, mathematicians usually refer to these polygons as n-gons, so an eight-sided polygon will be an 8-gon.

We can conclude that the three valid names for an octagon are: octagon, eight-sided polygon, and 8-gon.