This small macro create a circle or arc giving radius, diameter, circumference, area, startangle, endangle, arc, anglecenter, cord, arrow, center (point), placemObject on choice. The circle is still facing the screen (with getCameraOrientation) (or give the placement)

circle.FCMacro

# -*- coding: utf-8 -*-
# creer un cercle ou un arc entierement parametrabel en utilisant :
# create a circle or arc fully parametrabel using:
# x x x coordinates
#with radius
#with diameter
#with circumference
#with area
#with startangle
#with endangle
#with [arc and anglecenter]      in combination (angle in degrees)
#with [cord and arrow]           in combination
#with center (if center as different 0 one point is created on center of circle)
#give placemObject  
# ex :pl=FreeCAD.Placement()
#     pl.Rotation.Q=(0.0,-0.0,-0.0,1.0)
#     pl.Base=FreeCAD.Vector(-1.89847898483,-0.490152746439,0.0)
#     placemObject = pl
# s'il n'y a pas de parametre "circle()" une liste des fonctions s'affiche dans la Vue rapport
# if there is no parameter "circle()" a list of functions is displayed in the report view

__title__   = "circle"
__author__  = "Mario52"
__date__    = "10/06/2018"

import Draft #, Part
def circle(x=0.0,y=0.0,z=0.0,radius=0.0,diameter=0.0,circumference=0.0,area=0.0,startangle=0.0,endangle=0.0,arc=0.0,anglecenter=0.0,cord=0.0,arrow=0.0,center=0,placemObject=""):
    from math import sqrt, pi
    if placemObject == "":
        pl = FreeCAD.Placement()
        pl.Rotation = FreeCADGui.ActiveDocument.ActiveView.getCameraOrientation()   
        pl.Base = FreeCAD.Vector(x,y,z)
    else:
        pl = placemObject                                  # placement imposted

    if diameter != 0:                                      # with diameter
        radius = diameter / 2.0
    elif circumference != 0:                               # with circumference
        radius = (circumference / pi) / 2.0
    elif area != 0:                                        # with area
        radius =  sqrt((area / pi))
    elif (cord != 0) and (arrow != 0):                     # with cord and arrow
        radius = ((arrow**2) + (cord**2) / 4.0) / (arrow*2) 
    elif (arc != 0) and (anglecenter != 0):                # with arc and anglecenter central in degrees
        radius = ((360/anglecenter)*arc) / pi/2.0
        if endangle != 0:
            startangle  = endangle - anglecenter
        endangle   = anglecenter + startangle
        startangle  = endangle - anglecenter

    if radius != 0:
        try:
            Draft.makeCircle(radius,placement=pl,face=False,startangle=startangle,endangle=endangle,support=None)
            if center != 0:
                Draft.makePoint(x,y,z)
        except Exception:
            App.Console.PrintError("Unexpected keyword argument" + "\n")
    else:
        App.Console.PrintMessage("Unexpected keyword argument" + "\n")
        App.Console.PrintMessage("circle(x,y,z,radius,diameter,circumference,area,startangle,endangle,[arc,anglecenter],[cord,arrow],center,placemObject)" + "\n")

#example
#circle(arc=50,anglecenter=20,center=1)
#circle(x=65,y=-15,arc=3.5,anglecenter=40,startangle=20,center=1)
#circle(5)
#circle(cord=140,arrow=42)

This macro utility is intended for the use of the program FreeCAD http://www.freecadweb.org/