EXPLANATION
Measure of the rectangular window:
length = 24 inches
width = 18 1/4 inches = 73/4 inches = 18.25 inches
The area is given by the following relationship:
[tex]\text{Area}_{wi\text{ndow}}=\text{length}\cdot\text{width}=24\cdot18.25=438in^2[/tex]The picture is as follows: