Oprah wants to know the difference in cross-sectional area of the door of her tent and the tent itself. The proportions of the tent are exactly the same as the door, as seen in the picture below. The triangular door has a length and height of w and h respectively.
The top of the tent is 3 cm higher than the door, and its ends are 4 cm longer than the ends of the door. Express the height of the tent in terms of h