Constant circle in scatter chart.

Trying to do a scatter chart in Power BI... Its on a 360 degree axis and looks something like this. I've set the x-axis constant line to 0 and y-axis constant line to 0. It plots dots based on values (currently only 1 value).

I'm looking to put a constant circle on the chart at 10%, just as an indication that whatever is within 10% is good, anything out of this is bad. Did a quick mock up on MS paint, my intended outcome is this.

Can this be done? Any help would be much appreciated!