Hello again Dr,
To circumscribe a square around a circle draw two diameters perpendicular to each other( one horizontal - one vertical to simplify exp.) Where the four points meet the circle draw two horiz and two vert tangents. Intersections of tangents define the square.
bjh
To inscribe a circle in a square bisect the sides of the square connect opposite points. The intersection of the lines between mid points of the sides is the centre of the circle and the radius is equal to a half side (or if using collapsing compasses the distance from the centre to any of the side mid points).
Also do not call this "square the circle" which is the name of a problem from classical antiquity to construct a square with the same area as a given circle using straight edge and compass only. This is impossible.
CB