From FreeCAD Documentation
- There are several ways to invoke the command:
- Press the Arc button.
- Select the Drafting → Arc tools → Arc option from the menu.
- Use the keyboard shortcut: A then R. introduced in version 0.20
- The Arc task panel opens. See Options for more information.
- Pick the first point, the center of the arc, in the 3D view, or type coordinates and press the Enter point button.
- Pick the second point in the 3D view, or enter a Radius.
- Pick the third point in the 3D view, or enter a Start angle.
- Pick the fourth point in the 3D view, or enter an Aperture angle.