I am trying to make a relation for a point in a new sketch to the centre of a circle I already cut extrude. But when I hover over the extruded cut circle, I don't get any centre point showing. The picture below shows what I am trying to do. I want to centre the box on the large circle in the middle so I can then space the small holes correctly.

I know I can just change extruded cut circle's sketch to 'show' but I feel there must be a quicker way. Can anyone offer any advice?