To determine the diameter of the window, we'll consider the information given and follow step-by-step reasoning:
1. The brace is mentioned to be 2 feet long. Since the brace goes through the frame and extends upward through the center, it functions as the radius of the circular window.
2. In a circle, the radius is half the length of the diameter.
3. Therefore, to find the diameter, we need to double the radius.
Since the radius is given as 2 feet, the diameter of the circular window is:
[tex]\[ \text{Diameter} = 2 \times \text{radius} = 2 \times 2 \text{ feet} = 4 \text{ feet} \][/tex]
So, the diameter of the window is:
[tex]\[ \boxed{4 \text{ feet}} \][/tex]
