I doubt if there's an easy answer to this one. Writing and debugging a VBA script would almost certainly take longer than doing it manually.

However, you can set the snapping parameters to make it easier to do it manually.

Tools : Options and under Workspace, select "Snap to Objects". Turn off everything except Snap To Objects, Use cursor position and snap to bounding box. Set snap threshold to High.

Also in the View menu, turn off snap to grid and snap to guidelines.

Now, if you select the rectangle tool, whenever you start drawing a rectangle starting from a position that's approximately level with top and side of a circle by dragging to the opposite corner, it will create a square that snaps to the edges of the circle. (Easier to do than to describe, just experiment if you're not sure what I mean).