To Place a Polygon with the Radius Defined Graphically

Select the Place Regular Polygon tool (Drawing > Home > Placement > Polygon Tools split button).
In the tool settings window's Radius field, key in 0.
Set Method to Inscribed or Circumscribed.
Enter a data point to define the center.
Enter a data point to define the radius of the imaginary circle, the polygon's rotation, and one vertex (inscribed) or the center of one side (circumscribed).
Return to step 4 to place additional polygons or Reset.

Place Regular Polygon with the Radius defined by a data point. Method is Inscribed (left), Circumscribed (right).