What are the angles of a seven sided building and how big are the walls to keep it under 200 square feet?

I believe the angles to an equilateral seven-sided building would be 128.57 degrees on each of the outside corners. An octagon would be 135 degrees; a hexagon 120 degrees; so it makes sense it would fall in between. To achieve a square footage under 200 square feet, I believe each outside wall would be approximately 7 feet long, and the distance to the center from the middle of an outside wall just over 7 1/2 feet.