The area of the square is 2 square units.
The three shapes are:
A small triangle
A medium triangle
A square
The small triangle is made up of two right triangles. The area of a right triangle is 1/2 base x height. So, the area of each small right triangle in the small triangle is 1/2 x 1/2 = 1/4 square unit. The area of the small triangle is 1/4 + 1/4 = 1/2 square unit.
The medium triangle is made up of four small triangles. So, the area of the medium triangle is 4 x 1/2 = 2 square units.
The square is made up of four small triangles.
So,
the area of the square is 4 x 1/2 = 2 square units.