Notice that the triangle is a right isosceles triangle, because the given angle measures are 45° and 90°, so the third angle measure is 180°-90°-45°=45°.
The length of the hypotenuse is 24 ft. Let the side lengths of the 2 equal sides be
a.
By the Pythagorean theorem we have:

thus

divide both sides by 2, and take the square root:

The area of the triangle is given by the formula:
(1/2)*side*side, so the area of the triangle is :
(1/2)*

*

=144 (square units)
Answer: 144 square units