We know the square is 16 in squared, so that's out of the way, now for the triangles.
Since there are four triangles, all the same size, we can just combine two of them to make it a rectangle, so we can figure this out a bit easier.
Since the length is 4 and the height is 3, we multiply those to get 12. Normally we would divide that by two to get the area of a triangle, but since we have four triangles, I say we just double it to reduce the work for us.
12 doubled is 24
24 plus 16 is 40
Your answer is 40 inches squared.
Any questions?