I've got a part that pivots relative to the top plane. I want to see the angle as I move the part in the assemble.

I create a part. Created a axis between the Top and Front assembly planes. Created a conincident mate between the edge of the part and th axist. Also created a conincident mate between rigth side of part and Right assmbly panle . I can drag the plan. I want to see the angle the between the part and the horizon (top) change as I move the plane. See attached

Thanks