How about this one Spawn???

Pythagoreom theorom, assuming that's a right triangle

sqrt(20^2+20^2 = 28.284

1. 28.284

2. 28.284

1/2bh

28.284*(1/2)*16 = 226.274

3. 226.274

226.274+(28.284^2) = 1026.259

4. 1026.259

All assuming that that is a right triangle

Don't answer it yet. Let me review my answer or another  person gives input. Been almost 3 years since done this stuff.

Each side of the square is 24 in. Long.  112-40=72/3=24

The side length is 24 in. 

24*.5(16) = 192in.² is the area of the triangle.

24^2 = 576in.² is the area of the square.

576+192 = 768in², so the total area is 768in.².