I think I'm beginning to get the idea of #FreeCAD's constraint's, but it's a *lot* of pointy-clicky:

* draw a construction line from the origin: constrain it horizontal and to length 9.9 mm
* draw an arc from left line end, constrain radius=5.5 mm;
* draw an arc from right line end, constrain radius=4.5 mm;
* draw two tangent-ish lines;
* for each of the 4 pairs of line/arc end points, select and constrain tangentially

cf. #OpenSCAD :
hull(){circle(5.5);translate([9.9,0])circle(4.5);}