octagon - An eight (8) sided polygon
Formula: P = 8s
OctagonFree Octagon Calculator - Calculate side, area, and perimeter of an octagon based on inputs
Octagonal NumberFree Octagonal Number Calculator - This calculator determines the nth octagonal number
PolygonsFree Polygons Calculator - Using various input scenarios of a polygon such as side length, number of sides, apothem, and radius, this calculator determines Perimeter or a polygon and Area of the polygon.
This also determines interior angles of a polygon and diagonals of a polygon as well as the total number of 1 vertex diagonals.