A window is in the shape of a semi-circle over a rectangle, as shown. The distance around the outside of the window is 12 metres. What dimensions will result in the rectangular portion of the window having the largest possible area?

6. A window is in the shape ofa semicircle over a rectangle, as shown. The distance around the outside of the window is 12 metres. What dimensions will result in the rectangular portion of the window having the largest possible area