This arc is defined by its two end points and any other point on the arc.
You can draw this arc in two ways.
|•||Click AND HOLD the left mouse button – this determines one end of the arc.|
|•||Move the mouse (while holding the button) to the other end of your arc. While you are moving the mouse, FX Draw will synthesize a third point and show you an arc. Release the button when you are at the second point.|
|•||Click AND HOLD the left mouse button and move the mouse to a third point on your arc. As you move the mouse, FX Draw will draw an arc defined by your points. Release the button when you are at the third point.|
Alternatively you can click three times - once on each point.