You must use sinθ=

first to identify AC,
sin45=

By cross multiplying!,,,
sin45× 24 = AC
AC= 16.97056275 (Rounded= 16.97)
So, now you have base! But the triangle's formula is

base× height,,, So , you need height which is BC,
To find BC,
You could use cos , tan or sin as well, but I find Pythagorean Theorem slightly easy, So I'll show you that ---
Which is,

+

=


+

=

So, we have AC= 16.97, and AB= 24
That's sufficient for what we want, let's plug in our values into the formula,

+

=

Moving

to right,,

=

-


= 576-288

= 288

=

( squaring both sides )
BC = 16.97 ft.
So, now we have Base = 16.97 and height same= 16.97
And now you can find the area,

× base × height

× 16.97 ×16.97
To get 96 square feet.