Dimension Arrow Size? Distance From That Other Thing? Arrowless Text Box

Yeah, I still can’t see that. if you look at the attached picture, I made a C-shape using rectangles. Now my project is to put the little rectangle EXACTLY equidistant from the C-shape edges. I can eyeball it and use the measuring tool, but I was asking is there a way that as I move the little rectangle in the C, little distance lines pop up to show me how far it is from the top and sides so I can quickly get it in the exact equidistant spot without all the tweaking. HTH. Regards, Leaning