To find the area of the figure,we nees to first find the length of AC and BC by sine formula:
The length of AC:
24/sin90°=AC/sin45°
AC=24/sin90° x sin45°
AC=16.9705..
AC≈16.97ft
<BAC=180°-90°-45°=45°
As there are two same angles,it is an isosceles triangle,thus BC=AC≈16.97ft
The area:
16.97×16.97/2
=143.99...
≈144 sq.ft
Therefore, the answer is 144sq.ft
Hope it helps!