To draw the swing arm, utilize CAD commands like circleTTR for tangent circles and the polygon command to draw circumscribed/inscribed polygons.

Steps:

- Create an auxiliary line measuring 70 units.
- Place circles with the desired radius at both ends of the auxiliary line.
- Add centerlines to the circles using the “Draw-special line -circle centerline” command.
- Utilize the CircleTTR command to draw tangent circles with radii of 50 and 150. (Ensure the tangent points are chosen in the approximate locations to prevent the tangent circle from being placed incorrectly.)
- Trim the circles.
- Draw an auxiliary line at an angle of 70 degrees.
- Use the auxiliary lines to draw circumscribed squares (C for circumscribed).
- Draw an inscribed regular hexagon (enter I for inscribed).
- Include annotations as needed.