In order to calculate the area of a semi-circle, we can use the formula below:
[tex]A=\frac{\pi r^2}{2}[/tex]
For pi = 3.14 and r = 40 cm, we have:
[tex]\begin{gathered} A=\frac{3.14\cdot40^2}{2} \\ A=\frac{3.14\cdot1600}{2} \\ A=3.14\cdot800 \\ A=2512\text{ cm}^2 \end{gathered}[/tex]
Therefore the window area is 2512 cm².
