In the graphics area, select the intersecting construction line.
The centerline you just sketched
should already be displayed in the PropertyManager under Selected
Entities. If it is not, select it as well.

In the PropertyManager,
under Add Relations, click Perpendicular
.
In the graphics area, select the center of the circle and the intersecting construction line you recently added.

In the PropertyManager,
under Add Relations, click Coincident
, then click
.
