Yet another way to solve it. Now it is all Pathagorean.

View attachment 465621

That is how I solved it. And get the 436.xxx as well.

But that is making the ASSUMPTION that the other diagonal leg is ALSO 24'. That wasnt a given as per the first drawing. As it stands, how the drawing is sketched up with current dimensions, and not knowing that it is symmetrical.....it is technically impossible to figure without some other numbers. Either angles, or length of the other diagonal.

Gathering more facts and knowing it is for a driveway apron.....I hope we can assume it will be symmetrical. Thus the conclusion of 436.xxx sq ft.

But its usually not good to automatically assume things in problems like this.

Exaggerated example, but solve this: