Blue Octagon Shape

This image features a distinct blue octagon, an eight-sided polygon, set against a dark background. A prominent red arrow originates from the center of the octagon and extends to one of its vertices, where it is clearly labeled with the letter 'r'. This 'r' likely signifies the circumradius of the shape, connecting the center to a corner. Near the upper right vertex, there's also a smaller red dashed line segment, possibly highlighting a side or a section of the perimeter, adding to the geometric details presented.

octagon - blue - shape - polygon - radius - geometry - diagram - measure - form