From a drafting perspective, 378° circle does not make sense.
If you are interested in having 7 slices of 54° then you can proceed as follows:
1/ create a 3 point arc choosing the center and radius
2/ click on rotate, choose the arc then the center. Start point is one tip of arc and the end of point is the other one.
3/ In the rotation dialog window: choose multiple and enter 7 then for the angle enter 54°.
Fabrice
French hobbyist interested in 2D design.